Notes: m = 2 kg. v = 4 ms. Unknown: kinetic energy.
How we got there
Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.
Explain in another language · 11
1. What is the question asking?
Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: K = ½mv². m=2 kg, v=4 ms. K?
Before any working — hunt first
Given
Numbers and units already in the sentence: 2 kg · 4 ms. Copy each one into a column. A name without a number is not given.
Missing
After you copy the given, the letter that still has no number is missing. The paper is pointing at: K. Circle that word — that is the missing variable.
Find
We are required to find: K. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate
Write v² = 16 with empty letters. Cross out every letter that already has a number. Calculate the letter that is still standing — that gives K.
In other words — as if you have never seen this before
K = ½ m v². Square v first, then multiply.
2. What do we already know?
m = 2 kg. v = 4 ms. Unknown: kinetic energy.
3. Which method — and why this one?
K = ½ m v². Square v first, then multiply.
4. Step-by-step working
01 / 05
Square v
v²=16.
v²=16
Why this step: One job per line so you can find a slip, and so a marker can follow the marks.
02 / 05
Substitute
K=½×2×16=16 J.
K=16 J
Why this step: Write the formula before numbers. The memo awards a method mark even if a digit slips later.
03 / 05
Step G — Sense-check the size
Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.
Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.
04 / 05
Step F — Box the answer with its unit
16 J
Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.
05 / 05
Step H — What the marker is looking for
On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.
Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.
5. The answer
16 J
Copy onto your answer sheet — in this order
Formula: v²=16
Answer: 16 J
6. Check it like a marker
½×2=1, then×16=16. Units kg·m²s²=J.
7. A trap first-timers fall into
½×2×4 = 4 forgets to square v. The ² is not decoration.
Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.
Explain in another language · 11
1. What is the question asking?
Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: Ep = mgh. m=3 kg, h=5 m, g=10. Ep?
Before any working — hunt first
Given
Numbers and units already in the sentence: 3 kg · 5 m · 10. Copy each one into a column. A name without a number is not given.
Missing
After you copy the given, the letter that still has no number is missing. The paper is pointing at: Ep. Circle that word — that is the missing variable.
Find
We are required to find: Ep. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate
Write Ep = 150 J with empty letters. Cross out every letter that already has a number. Calculate the letter that is still standing — that gives Ep.
In other words — as if you have never seen this before
Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
02 / 08
Step A2 — Hunt: Given, Missing, Find, Calculate
Given: Numbers and units already in the sentence: 3 kg · 5 m · 10. Copy each one into a column. A name without a number is not given.
Missing: After you copy the given, the letter that still has no number is missing. The paper is pointing at: Ep. Circle that word — that is the missing variable.
Find: We are required to find: Ep. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate: Write Ep = 150 J with empty letters. Cross out every letter that already has a number. Calculate the letter that is still standing — that gives Ep.
Why this step: Do not name the letters yet. First hunt: what already has a number (Given), what has no number (Missing), the word the paper wants (Find), and which formula still contains the missing letter (Calculate).
Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.
04 / 08
Step C — Name the method in words
Ep = m g h. Three-factor product.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
05 / 08
Multiply
3×10×5=150 J.
Ep=150 J
Why this step: Write the formula before numbers. The memo awards a method mark even if a digit slips later.
06 / 08
Step G — Sense-check the size
Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.
Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.
07 / 08
Step F — Box the answer with its unit
150 J
Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.
08 / 08
Step H — What the marker is looking for
On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.
Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.
5. The answer
150 J
Copy onto your answer sheet — in this order
Formula: Ep=150 J
Answer: 150 J
6. Check it like a marker
Weight 30 N through 5 m is 150 J of work against gravity.
7. A trap first-timers fall into
m+g+h = 18 is adding unlike quantities.
2.1 · 10 Marks
A 6 N force does work through 3 m in the direction of F. W?
Notes: F = 6 N. Δx = 3 m. Force parallel to displacement.
How we got there
Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.
Explain in another language · 11
1. What is the question asking?
Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: A 6 N force does work through 3 m in the direction of F. W?
Before any working — hunt first
Given
Numbers and units already in the sentence: 6 N · 3 m. Copy each one into a column. A name without a number is not given.
Missing
After you copy the given, the letter that still has no number is missing. The paper is pointing at: W. Circle that word — that is the missing variable.
Find
We are required to find: W. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate
Write W = 18 J with empty letters. Cross out every letter that already has a number. Calculate the letter that is still standing — that gives W.
In other words — as if you have never seen this before
W=F Δx cosθ. θ=0 so cos=1.
2. What do we already know?
F = 6 N. Δx = 3 m. Force parallel to displacement.
3. Which method — and why this one?
W=F Δx cosθ. θ=0 so cos=1.
4. Step-by-step working
01 / 08
Step A — Read the question twice
Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
02 / 08
Step A2 — Hunt: Given, Missing, Find, Calculate
Given: Numbers and units already in the sentence: 6 N · 3 m. Copy each one into a column. A name without a number is not given.
Missing: After you copy the given, the letter that still has no number is missing. The paper is pointing at: W. Circle that word — that is the missing variable.
Find: We are required to find: W. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate: Write W = 18 J with empty letters. Cross out every letter that already has a number. Calculate the letter that is still standing — that gives W.
Why this step: Do not name the letters yet. First hunt: what already has a number (Given), what has no number (Missing), the word the paper wants (Find), and which formula still contains the missing letter (Calculate).
03 / 08
Step B — Write the given in a column
F = 6 N. Δx = 3 m. Force parallel to displacement.
Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.
04 / 08
Step C — Name the method in words
W=F Δx cosθ. θ=0 so cos=1.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
05 / 08
W = FΔx
W=6×3=18 J.
W=18 J
Why this step: Write the formula before numbers. The memo awards a method mark even if a digit slips later.
06 / 08
Step G — Sense-check the size
Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.
Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.
07 / 08
Step F — Box the answer with its unit
18 J
Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.
08 / 08
Step H — What the marker is looking for
On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.
Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.
5. The answer
18 J
Copy onto your answer sheet — in this order
Formula: W=18 J
Answer: 18 J
6. Check it like a marker
Joule is N·m. 6 N through 3 m is 18 J.
7. A trap first-timers fall into
If the force were perpendicular, work would be 0. Here it is parallel.
2.2 · 12 Marks
Impulse = Δp. F=10 N for 0.5 s. Δp?
Notes: F=10 N. Δt=0.5 s. Impulse J=F Δt=Δp.
How we got there
Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.
Explain in another language · 11
1. What is the question asking?
Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: Impulse = Δp. F=10 N for 0.5 s. Δp?
Before any working — hunt first
Given
Numbers and units already in the sentence: 10 N · 0.5 s. Copy each one into a column. A name without a number is not given.
Missing
After you copy the given, the letter that still has no number is missing. The paper is pointing at: Δp. Circle that word — that is the missing variable.
Find
We are required to find: Δp. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate
Write Δp = 5 N·s with empty letters. Cross out every letter that already has a number. Calculate the letter that is still standing — that gives Δp.
In other words — as if you have never seen this before
Impulse is force times time. It equals the change in momentum.
2. What do we already know?
F=10 N. Δt=0.5 s. Impulse J=F Δt=Δp.
3. Which method — and why this one?
Impulse is force times time. It equals the change in momentum.
4. Step-by-step working
01 / 08
Step A — Read the question twice
Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
02 / 08
Step A2 — Hunt: Given, Missing, Find, Calculate
Given: Numbers and units already in the sentence: 10 N · 0.5 s. Copy each one into a column. A name without a number is not given.
Missing: After you copy the given, the letter that still has no number is missing. The paper is pointing at: Δp. Circle that word — that is the missing variable.
Find: We are required to find: Δp. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate: Write Δp = 5 N·s with empty letters. Cross out every letter that already has a number. Calculate the letter that is still standing — that gives Δp.
Why this step: Do not name the letters yet. First hunt: what already has a number (Given), what has no number (Missing), the word the paper wants (Find), and which formula still contains the missing letter (Calculate).
03 / 08
Step B — Write the given in a column
F=10 N. Δt=0.5 s. Impulse J=F Δt=Δp.
Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.
04 / 08
Step C — Name the method in words
Impulse is force times time. It equals the change in momentum.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
05 / 08
J = FΔt
J=10×0.5=5 N·s.
Δp=5 N·s
Why this step: Write the formula before numbers. The memo awards a method mark even if a digit slips later.
06 / 08
Step G — Sense-check the size
Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.
Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.
07 / 08
Step F — Box the answer with its unit
5 N·s
Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.
08 / 08
Step H — What the marker is looking for
On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.
Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.
5. The answer
5 N·s
Copy onto your answer sheet — in this order
Formula: Δp=5 N·s
Answer: 5 N·s
6. Check it like a marker
N·s = kg·ms, the unit of momentum.
7. A trap first-timers fall into
F/Δt is not impulse. That would be a jerk, not a mark.
5 · 3 Marks
Doppler: source towards you. Observed f is
Notes: Source moving towards a stationary listener.
How we got there
Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.
Explain in another language · 11
1. What is the question asking?
Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: Doppler: source towards you. Observed f is
Before any working — hunt first
Given
Numbers and units already in the sentence: no numbers yet — only a name, a diagram, or a worded unknown. Copy each one into a column. A name without a number is not given.
Missing
After you copy the given, the letter that still has no number is missing. The paper is pointing at: Observed f is. Circle that word — that is the missing variable.
Find
We are required to find: Observed f is. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate
Write f' > f with empty letters. Cross out every letter that already has a number. Calculate the letter that is still standing — that gives Observed f is.
In other words — as if you have never seen this before
Crests bunch up ahead of a moving source. Pitch rises.
2. What do we already know?
Source moving towards a stationary listener.
3. Which method — and why this one?
Crests bunch up ahead of a moving source. Pitch rises.
4. Step-by-step working
01 / 08
Step A — Read the question twice
Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
02 / 08
Step A2 — Hunt: Given, Missing, Find, Calculate
Given: Numbers and units already in the sentence: no numbers yet — only a name, a diagram, or a worded unknown. Copy each one into a column. A name without a number is not given.
Missing: After you copy the given, the letter that still has no number is missing. The paper is pointing at: Observed f is. Circle that word — that is the missing variable.
Find: We are required to find: Observed f is. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate: Write f' > f with empty letters. Cross out every letter that already has a number. Calculate the letter that is still standing — that gives Observed f is.
Why this step: Do not name the letters yet. First hunt: what already has a number (Given), what has no number (Missing), the word the paper wants (Find), and which formula still contains the missing letter (Calculate).
03 / 08
Step B — Write the given in a column
Source moving towards a stationary listener.
Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.
04 / 08
Step C — Name the method in words
Crests bunch up ahead of a moving source. Pitch rises.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
05 / 08
Picture crests
Wavelength in front shrinks, so f = v/λ rises.
f' > f
Why this step: Write the formula before numbers. The memo awards a method mark even if a digit slips later.
06 / 08
Step G — Sense-check the size
Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.
Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.
07 / 08
Step F — Box the answer with its unit
higher
Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.
08 / 08
Step H — What the marker is looking for
On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.
Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.
5. The answer
higher
Copy onto your answer sheet — in this order
Formula: f' > f
Answer: higher
6. Check it like a marker
Ambulance siren rises as it comes toward you.
7. A trap first-timers fall into
Do not swap source and listener formulas on the data sheet.
6 · 3 Marks · Friction
Static friction can be
Friction
Formulas
fs ≤ μs N
Static friction (maximum at the point of slipping)
fk=μk N
Kinetic friction
How we got there
Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.
Explain in another language · 11
1. What is the question asking?
Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: Static friction can be
Before any working — hunt first
Given
Numbers and units already in the sentence: no numbers yet — only a name, a diagram, or a worded unknown. Copy each one into a column. A name without a number is not given.
Missing
After you copy the given, the letter that still has no number is missing. The paper is pointing at: Static friction can be. Circle that word — that is the missing variable.
Find
We are required to find: Static friction can be. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate
What we need to calculate: Only the maximum is μ_s N. Then substitute the given, one line at a time, to get Static friction can be.
In other words — as if you have never seen this before
Only the maximum is μ_s N.
2. What do we already know?
Copy these onto the left of your page, one per line, with units: every number and its unit in the sentence. Mixing cm with m, or minutes with seconds, loses a method mark.
3. Which method — and why this one?
Only the maximum is μ_s N.
4. Step-by-step working
01 / 08
Step A — Read the question twice
Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
02 / 08
Step A2 — Hunt: Given, Missing, Find, Calculate
Given: Numbers and units already in the sentence: no numbers yet — only a name, a diagram, or a worded unknown. Copy each one into a column. A name without a number is not given.
Missing: After you copy the given, the letter that still has no number is missing. The paper is pointing at: Static friction can be. Circle that word — that is the missing variable.
Find: We are required to find: Static friction can be. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate: What we need to calculate: Only the maximum is μ_s N. Then substitute the given, one line at a time, to get Static friction can be.
Why this step: Do not name the letters yet. First hunt: what already has a number (Given), what has no number (Missing), the word the paper wants (Find), and which formula still contains the missing letter (Calculate).
03 / 08
Step B — Write the given in a column
Copy these onto the left of your page, one per line, with units: every number and its unit in the sentence. Mixing cm with m, or minutes with seconds, loses a method mark.
Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.
04 / 08
Step C — Name the method in words
Only the maximum is μ_s N.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
05 / 08
Working
Only the maximum is μ_s N.
Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.
06 / 08
Step G — Sense-check the size
Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.
Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.
07 / 08
Step F — Box the answer with its unit
any value from 0 up to μ_s N
Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.
08 / 08
Step H — What the marker is looking for
On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.
Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.
5. The answer
any value from 0 up to μ_s N
Copy onto your answer sheet — in this order
Answer: any value from 0 up to μ_s N
6. Check it like a marker
Does your answer appear as one of the options? Do the units match what was asked (m, N, J, °)? If you put the number back into the original equation, does it still hold? Estimate: is the size sensible?
7. A trap first-timers fall into
First-timers often grab the first formula they remember, mix units (cm with m, minutes with seconds), or drop a minus sign. Write the formula in words first: “this equals that, because…”
7 · 2 Marks · Refraction & TIR
TIR happens when light goes
Refraction & TIR
Formulas
n₁ sinθ₁=n₂ sinθ₂
Snell’s law
How we got there
Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.
Explain in another language · 11
1. What is the question asking?
Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: TIR happens when light goes
Before any working — hunt first
Given
Numbers and units already in the sentence: no numbers yet — only a name, a diagram, or a worded unknown. Copy each one into a column. A name without a number is not given.
Missing
After you copy the given, the letter that still has no number is missing. The paper is pointing at: TIR happens when light goes. Circle that word — that is the missing variable.
Find
We are required to find: TIR happens when light goes. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate
What we need to calculate: denser. Then substitute the given, one line at a time, to get TIR happens when light goes.
In other words — as if you have never seen this before
denser → rarer, i > c
2. What do we already know?
Copy these onto the left of your page, one per line, with units: every number and its unit in the sentence. Mixing cm with m, or minutes with seconds, loses a method mark.
3. Which method — and why this one?
denser → rarer, i > c
4. Step-by-step working
01 / 08
Step A — Read the question twice
Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
02 / 08
Step A2 — Hunt: Given, Missing, Find, Calculate
Given: Numbers and units already in the sentence: no numbers yet — only a name, a diagram, or a worded unknown. Copy each one into a column. A name without a number is not given.
Missing: After you copy the given, the letter that still has no number is missing. The paper is pointing at: TIR happens when light goes. Circle that word — that is the missing variable.
Find: We are required to find: TIR happens when light goes. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate: What we need to calculate: denser. Then substitute the given, one line at a time, to get TIR happens when light goes.
Why this step: Do not name the letters yet. First hunt: what already has a number (Given), what has no number (Missing), the word the paper wants (Find), and which formula still contains the missing letter (Calculate).
03 / 08
Step B — Write the given in a column
Copy these onto the left of your page, one per line, with units: every number and its unit in the sentence. Mixing cm with m, or minutes with seconds, loses a method mark.
Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.
04 / 08
Step C — Name the method in words
denser → rarer, i > c
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
05 / 08
Reason
Critical angle condition.
Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.
06 / 08
Step G — Sense-check the size
Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.
Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.
07 / 08
Step F — Box the answer with its unit
denser → rarer, i > c
Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.
08 / 08
Step H — What the marker is looking for
On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.
Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.
5. The answer
denser → rarer, i > c
Copy onto your answer sheet — in this order
Answer: denser → rarer, i > c
6. Check it like a marker
Does your answer appear as one of the options? Do the units match what was asked (m, N, J, °)? If you put the number back into the original equation, does it still hold? Estimate: is the size sensible?
7. A trap first-timers fall into
First-timers often grab the first formula they remember, mix units (cm with m, minutes with seconds), or drop a minus sign. Write the formula in words first: “this equals that, because…”
8 · 2 Marks
Between parallel plates 200 V apart 0.05 m. E =
How we got there
Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.
Explain in another language · 11
1. What is the question asking?
Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: Between parallel plates 200 V apart 0.05 m. E =
Before any working — hunt first
Given
Numbers and units already in the sentence: 200 V · 0.05 m. Copy each one into a column. A name without a number is not given.
Missing
After you copy the given, the letter that still has no number is missing. The paper is pointing at: E =. Circle that word — that is the missing variable.
Find
We are required to find: E =. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate
What we need to calculate: E=Vd=2000. Then substitute the given, one line at a time, to get E =.
In other words — as if you have never seen this before
E=Vd=2000.05=4000.
2. What do we already know?
Copy these onto the left of your page, one per line, with units: 200 V · 0.05 m. Mixing cm with m, or minutes with seconds, loses a method mark.
3. Which method — and why this one?
E=Vd=2000.05=4000.
4. Step-by-step working
01 / 08
Step A — Read the question twice
Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
02 / 08
Step A2 — Hunt: Given, Missing, Find, Calculate
Given: Numbers and units already in the sentence: 200 V · 0.05 m. Copy each one into a column. A name without a number is not given.
Missing: After you copy the given, the letter that still has no number is missing. The paper is pointing at: E =. Circle that word — that is the missing variable.
Find: We are required to find: E =. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate: What we need to calculate: E=Vd=2000. Then substitute the given, one line at a time, to get E =.
Why this step: Do not name the letters yet. First hunt: what already has a number (Given), what has no number (Missing), the word the paper wants (Find), and which formula still contains the missing letter (Calculate).
03 / 08
Step B — Write the given in a column
Copy these onto the left of your page, one per line, with units: 200 V · 0.05 m. Mixing cm with m, or minutes with seconds, loses a method mark.
Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.
04 / 08
Step C — Name the method in words
E=Vd=2000.05=4000.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
05 / 08
Working
E=Vd=2000.05=4000.
Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.
06 / 08
Step G — Sense-check the size
Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.
Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.
07 / 08
Step F — Box the answer with its unit
4000 N·C⁻¹
Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.
08 / 08
Step H — What the marker is looking for
On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.
Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.
5. The answer
4000 N·C⁻¹
Copy onto your answer sheet — in this order
Answer: 4000 N·C⁻¹
6. Check it like a marker
Does your answer appear as one of the options? Do the units match what was asked (m, N, J, °)? If you put the number back into the original equation, does it still hold? Estimate: is the size sensible?
7. A trap first-timers fall into
First-timers often grab the first formula they remember, mix units (cm with m, minutes with seconds), or drop a minus sign. Write the formula in words first: “this equals that, because…”
9 · 2 Marks
ε=12 V, r=2 Ω, R=4 Ω. I=
How we got there
Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.
Explain in another language · 11
1. What is the question asking?
Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: ε=12 V, r=2 Ω, R=4 Ω. I =
Before any working — hunt first
Given
Numbers and units already in the sentence: 12 V · 2 Ω · 4 Ω. Copy each one into a column. A name without a number is not given.
Missing
After you copy the given, the letter that still has no number is missing. The paper is pointing at: I =. Circle that word — that is the missing variable.
Find
We are required to find: I =. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate
What we need to calculate: 2 A. Then substitute the given, one line at a time, to get I =.
In other words — as if you have never seen this before
2 A
2. What do we already know?
Copy these onto the left of your page, one per line, with units: 12 V · 2 Ω · 4 Ω. Mixing cm with m, or minutes with seconds, loses a method mark.
3. Which method — and why this one?
2 A
4. Step-by-step working
01 / 08
Step A — Read the question twice
Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
02 / 08
Step A2 — Hunt: Given, Missing, Find, Calculate
Given: Numbers and units already in the sentence: 12 V · 2 Ω · 4 Ω. Copy each one into a column. A name without a number is not given.
Missing: After you copy the given, the letter that still has no number is missing. The paper is pointing at: I =. Circle that word — that is the missing variable.
Find: We are required to find: I =. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate: What we need to calculate: 2 A. Then substitute the given, one line at a time, to get I =.
Why this step: Do not name the letters yet. First hunt: what already has a number (Given), what has no number (Missing), the word the paper wants (Find), and which formula still contains the missing letter (Calculate).
03 / 08
Step B — Write the given in a column
Copy these onto the left of your page, one per line, with units: 12 V · 2 Ω · 4 Ω. Mixing cm with m, or minutes with seconds, loses a method mark.
Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.
04 / 08
Step C — Name the method in words
2 A
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
05 / 08
Reason
I=12(4+2)=2 A.
Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.
06 / 08
Step G — Sense-check the size
Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.
Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.
07 / 08
Step F — Box the answer with its unit
2 A
Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.
08 / 08
Step H — What the marker is looking for
On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.
Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.
5. The answer
2 A
Copy onto your answer sheet — in this order
Answer: 2 A
6. Check it like a marker
Does your answer appear as one of the options? Do the units match what was asked (m, N, J, °)? If you put the number back into the original equation, does it still hold? Estimate: is the size sensible?
7. A trap first-timers fall into
First-timers often grab the first formula they remember, mix units (cm with m, minutes with seconds), or drop a minus sign. Write the formula in words first: “this equals that, because…”
10 · 2 Marks
G in F=Gm₁m₂/r² is
How we got there
Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.
Explain in another language · 11
1. What is the question asking?
Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: G in F=Gm₁m₂/r² is
Before any working — hunt first
Given
Numbers and units already in the sentence: no numbers yet — only a name, a diagram, or a worded unknown. Copy each one into a column. A name without a number is not given.
Missing
After you copy the given, the letter that still has no number is missing. The paper is pointing at: G in F=Gm₁m₂/r² is. Circle that word — that is the missing variable.
Find
We are required to find: G in F=Gm₁m₂/r² is. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate
What we need to calculate: G = 6. Then substitute the given, one line at a time, to get G in F=Gm₁m₂/r² is.
In other words — as if you have never seen this before
G=6.67×10⁻¹¹ N·m²·kg⁻².
2. What do we already know?
Copy these onto the left of your page, one per line, with units: every number and its unit in the sentence. Mixing cm with m, or minutes with seconds, loses a method mark.
3. Which method — and why this one?
G=6.67×10⁻¹¹ N·m²·kg⁻².
4. Step-by-step working
01 / 08
Step A — Read the question twice
Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
02 / 08
Step A2 — Hunt: Given, Missing, Find, Calculate
Given: Numbers and units already in the sentence: no numbers yet — only a name, a diagram, or a worded unknown. Copy each one into a column. A name without a number is not given.
Missing: After you copy the given, the letter that still has no number is missing. The paper is pointing at: G in F=Gm₁m₂/r² is. Circle that word — that is the missing variable.
Find: We are required to find: G in F=Gm₁m₂/r² is. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate: What we need to calculate: G = 6. Then substitute the given, one line at a time, to get G in F=Gm₁m₂/r² is.
Why this step: Do not name the letters yet. First hunt: what already has a number (Given), what has no number (Missing), the word the paper wants (Find), and which formula still contains the missing letter (Calculate).
03 / 08
Step B — Write the given in a column
Copy these onto the left of your page, one per line, with units: every number and its unit in the sentence. Mixing cm with m, or minutes with seconds, loses a method mark.
Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.
04 / 08
Step C — Name the method in words
G=6.67×10⁻¹¹ N·m²·kg⁻².
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
05 / 08
Working
G=6.67×10⁻¹¹ N·m²·kg⁻².
Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.
06 / 08
Step G — Sense-check the size
Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.
Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.
07 / 08
Step F — Box the answer with its unit
universal gravitational constant
Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.
08 / 08
Step H — What the marker is looking for
On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.
Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.
5. The answer
universal gravitational constant
Copy onto your answer sheet — in this order
Answer: universal gravitational constant
6. Check it like a marker
Does your answer appear as one of the options? Do the units match what was asked (m, N, J, °)? If you put the number back into the original equation, does it still hold? Estimate: is the size sensible?
7. A trap first-timers fall into
First-timers often grab the first formula they remember, mix units (cm with m, minutes with seconds), or drop a minus sign. Write the formula in words first: “this equals that, because…”
11 · 2 Marks
Two 6 Ω resistors in parallel. R_eq =
Notes: R₁ = 6 Ω, R₂ = 6 Ω, connected in parallel (side by side, two paths).
How we got there
Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.
Explain in another language · 11
1. What is the question asking?
Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: Two 6 Ω resistors in parallel. R_eq =
Before any working — hunt first
Given
Numbers and units already in the sentence: 6 Ω. Copy each one into a column. A name without a number is not given.
Missing
After you copy the given, the letter that still has no number is missing. The paper is pointing at: R_eq =. Circle that word — that is the missing variable.
Find
We are required to find: R_eq =. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate
Write 1Req=1R₁ + 1R₂ with empty letters. Cross out every letter that already has a number. Calculate the letter that is still standing — that gives R_eq =.
In other words — as if you have never seen this before
Parallel: the reciprocals add. Equal parallels always halve. Series would have added to 12 Ω.
2. What do we already know?
R₁ = 6 Ω, R₂ = 6 Ω, connected in parallel (side by side, two paths).
3. Which method — and why this one?
Parallel: the reciprocals add. Equal parallels always halve. Series would have added to 12 Ω.
4. Step-by-step working
01 / 05
Write the parallel law
1Req=1R₁ + 1R₂. For two equals this becomes 1R + 1R=2R, so R_eq = R2.
1Req=1R₁+1R₂
Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.
02 / 05
Substitute
1Req=16+16=26=13. Flip both sides: Req=3 Ω.
Req=3 Ω
Why this step: Flipping 1/3 gives 3. First-timers stop at 1/3 and write 0.33 Ω — they forgot to invert.
03 / 05
Step G — Sense-check the size
Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.
Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.
04 / 05
Step F — Box the answer with its unit
3 Ω
Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.
05 / 05
Step H — What the marker is looking for
On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.
Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.
5. The answer
3 Ω
Copy onto your answer sheet — in this order
Formula: 1Req=1R₁+1R₂
Answer: 3 Ω
6. Check it like a marker
Equal parallels: half of 6 is 3. Parallel equivalent is always smaller than the smallest resistor (6). 3 < 6. Good.
7. A trap first-timers fall into
Adding 6+6=12. That is series. The question said parallel — two paths, current splits, resistance drops.
12 · 2 Marks · Friction
20 kg on horizontal floor, μ_s = 0.4, g = 9.8. Max static friction =
Friction
Formulas
fs ≤ μs N
Static friction (maximum at the point of slipping)
fk=μk N
Kinetic friction
How we got there
Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.
Explain in another language · 11
1. What is the question asking?
Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: 20 kg on horizontal floor, μ_s = 0.4, g = 9.8. Max static friction =
Before any working — hunt first
Given
Numbers and units already in the sentence: 20 kg · 0.4 · 9.8. Copy each one into a column. A name without a number is not given.
Missing
After you copy the given, the letter that still has no number is missing. The paper is pointing at: Max static friction =. Circle that word — that is the missing variable.
Find
We are required to find: Max static friction =. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate
What we need to calculate: N = 196 N. Then substitute the given, one line at a time, to get Max static friction =.
In other words — as if you have never seen this before
N=196 N. μs N=78.4 N.
2. What do we already know?
Copy these onto the left of your page, one per line, with units: 20 kg · 0.4 · 9.8. Mixing cm with m, or minutes with seconds, loses a method mark.
3. Which method — and why this one?
N=196 N. μs N=78.4 N.
4. Step-by-step working
01 / 08
Step A — Read the question twice
Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
02 / 08
Step A2 — Hunt: Given, Missing, Find, Calculate
Given: Numbers and units already in the sentence: 20 kg · 0.4 · 9.8. Copy each one into a column. A name without a number is not given.
Missing: After you copy the given, the letter that still has no number is missing. The paper is pointing at: Max static friction =. Circle that word — that is the missing variable.
Find: We are required to find: Max static friction =. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate: What we need to calculate: N = 196 N. Then substitute the given, one line at a time, to get Max static friction =.
Why this step: Do not name the letters yet. First hunt: what already has a number (Given), what has no number (Missing), the word the paper wants (Find), and which formula still contains the missing letter (Calculate).
03 / 08
Step B — Write the given in a column
Copy these onto the left of your page, one per line, with units: 20 kg · 0.4 · 9.8. Mixing cm with m, or minutes with seconds, loses a method mark.
Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.
04 / 08
Step C — Name the method in words
N=196 N. μs N=78.4 N.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
05 / 08
Working
N=196 N. μs N=78.4 N.
Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.
06 / 08
Step G — Sense-check the size
Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.
Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.
07 / 08
Step F — Box the answer with its unit
78.4 N
Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.
08 / 08
Step H — What the marker is looking for
On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.
Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.
5. The answer
78.4 N
Copy onto your answer sheet — in this order
Answer: 78.4 N
6. Check it like a marker
Does your answer appear as one of the options? Do the units match what was asked (m, N, J, °)? If you put the number back into the original equation, does it still hold? Estimate: is the size sensible?
7. A trap first-timers fall into
First-timers often grab the first formula they remember, mix units (cm with m, minutes with seconds), or drop a minus sign. Write the formula in words first: “this equals that, because…”
13 · 2 Marks
A wave: f=50 Hz, λ=2 m. Speed v?
Notes: f=50 Hz. λ=2 m. Unknown: wave speed v.
How we got there
Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.
Explain in another language · 11
1. What is the question asking?
Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: A wave: f = 50 Hz, λ = 2 m. Speed v?
Before any working — hunt first
Given
Numbers and units already in the sentence: 50 Hz · 2 m. Copy each one into a column. A name without a number is not given.
Missing
After you copy the given, the letter that still has no number is missing. The paper is pointing at: Speed v. Circle that word — that is the missing variable.
Find
We are required to find: Speed v. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate
Write v = fλ with empty letters. Cross out every letter that already has a number. Calculate the letter that is still standing — that gives Speed v.
In other words — as if you have never seen this before
v = f λ. Frequency times wavelength. Do not divide.
2. What do we already know?
f=50 Hz. λ=2 m. Unknown: wave speed v.
3. Which method — and why this one?
v = f λ. Frequency times wavelength. Do not divide.
4. Step-by-step working
01 / 05
Write the wave equation
v=f λ.
v=fλ
Why this step: Write the formula before numbers. The memo awards a method mark even if a digit slips later.
02 / 05
Substitute
v=50×2=100 m·s⁻¹.
v=100 ms
Why this step: One job per line so you can find a slip, and so a marker can follow the marks.
03 / 05
Step G — Sense-check the size
Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.
Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.
04 / 05
Step F — Box the answer with its unit
100 ms
Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.
05 / 05
Step H — What the marker is looking for
On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.
Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.
5. The answer
100 ms
Copy onto your answer sheet — in this order
Formula: v=fλ
Answer: 100 ms
6. Check it like a marker
T = 1f=0.02 s. In 0.02 s the wave travels 100×0.02 = 2 m = λ. Consistent.
7. A trap first-timers fall into
v = f/λ = 25 would be wrong. Speed is product, not quotient.
14 · 2 Marks
Fnet=30 N, m=6 kg. a=
How we got there
Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.
Explain in another language · 11
1. What is the question asking?
Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: F_net = 30 N, m = 6 kg. a =
Before any working — hunt first
Given
Numbers and units already in the sentence: 30 N · 6 kg. Copy each one into a column. A name without a number is not given.
Missing
After you copy the given, the letter that still has no number is missing. The paper is pointing at: a =. Circle that word — that is the missing variable.
Find
We are required to find: a =. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate
What we need to calculate: 5 m·s⁻². Then substitute the given, one line at a time, to get a =.
In other words — as if you have never seen this before
5 m·s⁻²
2. What do we already know?
Copy these onto the left of your page, one per line, with units: 30 N · 6 kg. Mixing cm with m, or minutes with seconds, loses a method mark.
3. Which method — and why this one?
5 m·s⁻²
4. Step-by-step working
01 / 08
Step A — Read the question twice
Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
02 / 08
Step A2 — Hunt: Given, Missing, Find, Calculate
Given: Numbers and units already in the sentence: 30 N · 6 kg. Copy each one into a column. A name without a number is not given.
Missing: After you copy the given, the letter that still has no number is missing. The paper is pointing at: a =. Circle that word — that is the missing variable.
Find: We are required to find: a =. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate: What we need to calculate: 5 m·s⁻². Then substitute the given, one line at a time, to get a =.
Why this step: Do not name the letters yet. First hunt: what already has a number (Given), what has no number (Missing), the word the paper wants (Find), and which formula still contains the missing letter (Calculate).
03 / 08
Step B — Write the given in a column
Copy these onto the left of your page, one per line, with units: 30 N · 6 kg. Mixing cm with m, or minutes with seconds, loses a method mark.
Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.
04 / 08
Step C — Name the method in words
5 m·s⁻²
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
05 / 08
Working
a=Fm=306=5 m·s⁻².
Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.
06 / 08
Step G — Sense-check the size
Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.
Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.
07 / 08
Step F — Box the answer with its unit
5 m·s⁻²
Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.
08 / 08
Step H — What the marker is looking for
On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.
Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.
5. The answer
5 m·s⁻²
Copy onto your answer sheet — in this order
Answer: 5 m·s⁻²
6. Check it like a marker
Does your answer appear as one of the options? Do the units match what was asked (m, N, J, °)? If you put the number back into the original equation, does it still hold? Estimate: is the size sensible?
7. A trap first-timers fall into
First-timers often grab the first formula they remember, mix units (cm with m, minutes with seconds), or drop a minus sign. Write the formula in words first: “this equals that, because…”
15 · 3 Marks
Weight of 8 kg on Earth (g=9.8)
How we got there
Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.
Explain in another language · 11
1. What is the question asking?
Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: Weight of 8 kg on Earth (g=9.8)
Before any working — hunt first
Given
Numbers and units already in the sentence: 8 kg · 9.8. Copy each one into a column. A name without a number is not given.
Missing
After you copy the given, the letter that still has no number is missing. The paper is pointing at: 8). Circle that word — that is the missing variable.
Find
We are required to find: 8). Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate
What we need to calculate: w=mg. Then substitute the given, one line at a time, to get 8).
In other words — as if you have never seen this before
w=mg.
2. What do we already know?
Copy these onto the left of your page, one per line, with units: 8 kg · 9.8. Mixing cm with m, or minutes with seconds, loses a method mark.
3. Which method — and why this one?
w=mg.
4. Step-by-step working
01 / 08
Step A — Read the question twice
Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
02 / 08
Step A2 — Hunt: Given, Missing, Find, Calculate
Given: Numbers and units already in the sentence: 8 kg · 9.8. Copy each one into a column. A name without a number is not given.
Missing: After you copy the given, the letter that still has no number is missing. The paper is pointing at: 8). Circle that word — that is the missing variable.
Find: We are required to find: 8). Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate: What we need to calculate: w=mg. Then substitute the given, one line at a time, to get 8).
Why this step: Do not name the letters yet. First hunt: what already has a number (Given), what has no number (Missing), the word the paper wants (Find), and which formula still contains the missing letter (Calculate).
03 / 08
Step B — Write the given in a column
Copy these onto the left of your page, one per line, with units: 8 kg · 9.8. Mixing cm with m, or minutes with seconds, loses a method mark.
Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.
04 / 08
Step C — Name the method in words
w=mg.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
05 / 08
Working
w=mg.
Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.
06 / 08
Step G — Sense-check the size
Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.
Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.
07 / 08
Step F — Box the answer with its unit
78.4 N
Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.
08 / 08
Step H — What the marker is looking for
On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.
Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.
5. The answer
78.4 N
Copy onto your answer sheet — in this order
Answer: 78.4 N
6. Check it like a marker
Does your answer appear as one of the options? Do the units match what was asked (m, N, J, °)? If you put the number back into the original equation, does it still hold? Estimate: is the size sensible?
7. A trap first-timers fall into
First-timers often grab the first formula they remember, mix units (cm with m, minutes with seconds), or drop a minus sign. Write the formula in words first: “this equals that, because…”
Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.
Explain in another language · 11
1. What is the question asking?
Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: Efficiency = usefulinput. Useful 80 J, input 100 J
Before any working — hunt first
Given
Numbers and units already in the sentence: 80 J · 100 J. Copy each one into a column. A name without a number is not given.
Missing
After you copy the given, the letter that still has no number is missing. The paper is pointing at: Useful 80 J, input 100 J. Circle that word — that is the missing variable.
Find
We are required to find: Useful 80 J, input 100 J. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate
Write 80% with empty letters. Cross out every letter that already has a number. Calculate the letter that is still standing — that gives Useful 80 J, input 100 J.
In other words — as if you have never seen this before
Efficiency = (useful / input) × 100%.
2. What do we already know?
Useful energy 80 J. Input 100 J.
3. Which method — and why this one?
Efficiency = (useful / input) × 100%.
4. Step-by-step working
01 / 08
Step A — Read the question twice
Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
02 / 08
Step A2 — Hunt: Given, Missing, Find, Calculate
Given: Numbers and units already in the sentence: 80 J · 100 J. Copy each one into a column. A name without a number is not given.
Missing: After you copy the given, the letter that still has no number is missing. The paper is pointing at: Useful 80 J, input 100 J. Circle that word — that is the missing variable.
Find: We are required to find: Useful 80 J, input 100 J. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate: Write 80% with empty letters. Cross out every letter that already has a number. Calculate the letter that is still standing — that gives Useful 80 J, input 100 J.
Why this step: Do not name the letters yet. First hunt: what already has a number (Given), what has no number (Missing), the word the paper wants (Find), and which formula still contains the missing letter (Calculate).
03 / 08
Step B — Write the given in a column
Useful energy 80 J. Input 100 J.
Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.
04 / 08
Step C — Name the method in words
Efficiency = (useful / input) × 100%.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
05 / 08
Divide then percent
80100=0.8=80%.
80%
Why this step: Write the formula before numbers. The memo awards a method mark even if a digit slips later.
06 / 08
Step G — Sense-check the size
Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.
Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.
07 / 08
Step F — Box the answer with its unit
80%
Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.
08 / 08
Step H — What the marker is looking for
On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.
Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.
5. The answer
80%
Copy onto your answer sheet — in this order
Formula: 80%
Answer: 80%
6. Check it like a marker
20 J was wasted. 80+20=100.
7. A trap first-timers fall into
Writing 80 without % loses the unit the memo wants.
17 · 2 Marks
A 10 N force at 0° to x-axis. F_x =
How we got there
Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.
Explain in another language · 11
1. What is the question asking?
Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: A 10 N force at 0° to x-axis. F_x =
Before any working — hunt first
Given
Numbers and units already in the sentence: 10 N · 0°. Copy each one into a column. A name without a number is not given.
Missing
After you copy the given, the letter that still has no number is missing. The paper is pointing at: F_x =. Circle that word — that is the missing variable.
Find
We are required to find: F_x =. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate
What we need to calculate: cos 0° = 1, so F_x = 10 N. Then substitute the given, one line at a time, to get F_x =.
In other words — as if you have never seen this before
cos 0°=1, so Fx=10 N.
2. What do we already know?
Copy these onto the left of your page, one per line, with units: 10 N · 0°. Mixing cm with m, or minutes with seconds, loses a method mark.
3. Which method — and why this one?
cos 0°=1, so Fx=10 N.
4. Step-by-step working
01 / 08
Step A — Read the question twice
Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
02 / 08
Step A2 — Hunt: Given, Missing, Find, Calculate
Given: Numbers and units already in the sentence: 10 N · 0°. Copy each one into a column. A name without a number is not given.
Missing: After you copy the given, the letter that still has no number is missing. The paper is pointing at: F_x =. Circle that word — that is the missing variable.
Find: We are required to find: F_x =. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate: What we need to calculate: cos 0° = 1, so F_x = 10 N. Then substitute the given, one line at a time, to get F_x =.
Why this step: Do not name the letters yet. First hunt: what already has a number (Given), what has no number (Missing), the word the paper wants (Find), and which formula still contains the missing letter (Calculate).
03 / 08
Step B — Write the given in a column
Copy these onto the left of your page, one per line, with units: 10 N · 0°. Mixing cm with m, or minutes with seconds, loses a method mark.
Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.
04 / 08
Step C — Name the method in words
cos 0°=1, so Fx=10 N.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
05 / 08
Working
cos 0°=1, so Fx=10 N.
Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.
06 / 08
Step G — Sense-check the size
Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.
Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.
07 / 08
Step F — Box the answer with its unit
10 N
Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.
08 / 08
Step H — What the marker is looking for
On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.
Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.
5. The answer
10 N
Copy onto your answer sheet — in this order
Answer: 10 N
6. Check it like a marker
Does your answer appear as one of the options? Do the units match what was asked (m, N, J, °)? If you put the number back into the original equation, does it still hold? Estimate: is the size sensible?
7. A trap first-timers fall into
First-timers often grab the first formula they remember, mix units (cm with m, minutes with seconds), or drop a minus sign. Write the formula in words first: “this equals that, because…”
18 · 3 Marks · Electrostatics: charge & Coulomb
e = 1.6×10⁻¹⁹ C. Charge of 5 electrons is
Electrostatics: charge & Coulomb
Formulas
Q=n e
Quantisation of charge
F=k Q₁ Q₂r²
Coulomb’s law
How we got there
Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.
Explain in another language · 11
1. What is the question asking?
Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: e = 1.6×10⁻¹⁹ C. Charge of 5 electrons is
Before any working — hunt first
Given
Numbers and units already in the sentence: 1.6 · 10⁻¹ · 5 electrons. Copy each one into a column. A name without a number is not given.
Missing
After you copy the given, the letter that still has no number is missing. The paper is pointing at: Charge of 5 electrons is. Circle that word — that is the missing variable.
Find
We are required to find: Charge of 5 electrons is. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate
What we need to calculate: Q = ne = 5 × 1. Then substitute the given, one line at a time, to get Charge of 5 electrons is.
In other words — as if you have never seen this before
Q=ne=5×1.6×10⁻¹⁹=8.0×10⁻¹⁹ C.
2. What do we already know?
Copy these onto the left of your page, one per line, with units: 1.6 · 10⁻¹ · 5 electrons. Mixing cm with m, or minutes with seconds, loses a method mark.
3. Which method — and why this one?
Q=ne=5×1.6×10⁻¹⁹=8.0×10⁻¹⁹ C.
4. Step-by-step working
01 / 08
Step A — Read the question twice
Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
02 / 08
Step A2 — Hunt: Given, Missing, Find, Calculate
Given: Numbers and units already in the sentence: 1.6 · 10⁻¹ · 5 electrons. Copy each one into a column. A name without a number is not given.
Missing: After you copy the given, the letter that still has no number is missing. The paper is pointing at: Charge of 5 electrons is. Circle that word — that is the missing variable.
Find: We are required to find: Charge of 5 electrons is. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate: What we need to calculate: Q = ne = 5 × 1. Then substitute the given, one line at a time, to get Charge of 5 electrons is.
Why this step: Do not name the letters yet. First hunt: what already has a number (Given), what has no number (Missing), the word the paper wants (Find), and which formula still contains the missing letter (Calculate).
03 / 08
Step B — Write the given in a column
Copy these onto the left of your page, one per line, with units: 1.6 · 10⁻¹ · 5 electrons. Mixing cm with m, or minutes with seconds, loses a method mark.
Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.
04 / 08
Step C — Name the method in words
Q=ne=5×1.6×10⁻¹⁹=8.0×10⁻¹⁹ C.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
05 / 08
Working
Q=ne=5×1.6×10⁻¹⁹=8.0×10⁻¹⁹ C.
Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.
06 / 08
Step G — Sense-check the size
Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.
Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.
07 / 08
Step F — Box the answer with its unit
8.0×10⁻¹⁹ C
Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.
08 / 08
Step H — What the marker is looking for
On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.
Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.
5. The answer
8.0×10⁻¹⁹ C
Copy onto your answer sheet — in this order
Answer: 8.0×10⁻¹⁹ C
6. Check it like a marker
Does your answer appear as one of the options? Do the units match what was asked (m, N, J, °)? If you put the number back into the original equation, does it still hold? Estimate: is the size sensible?
7. A trap first-timers fall into
First-timers often grab the first formula they remember, mix units (cm with m, minutes with seconds), or drop a minus sign. Write the formula in words first: “this equals that, because…”
19 · 2 Marks · Coulomb’s law & fields
If the distance in Coulomb's law triples, the force becomes
Coulomb’s law & fields
Formulas
F=k Q₁ Q₂r²
Coulomb’s law
Notes: If the distance in Coulomb's law triples, the force becomes
How we got there
Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.
Explain in another language · 11
1. What is the question asking?
Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: If the distance in Coulomb's law triples, the force becomes
In other words — as if you have never seen this before
F is proportional to 1r², so ×3 in r means ×19 in F.
2. What do we already know?
If the distance in Coulomb's law triples, the force becomes
3. Which method — and why this one?
F is proportional to 1r², so ×3 in r means ×19 in F.
4. Step-by-step working
01 / 07
Step A — Read the question twice
Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
02 / 07
Step B — Write the given in a column
If the distance in Coulomb's law triples, the force becomes
Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.
03 / 07
Step C — Name the method in words
F is proportional to 1r², so ×3 in r means ×19 in F.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
04 / 07
Working
F is proportional to 1r², so ×3 in r means ×19 in F.
Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.
05 / 07
Step G — Sense-check the size
Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.
Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.
06 / 07
Step F — Box the answer with its unit
19 as large
Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.
07 / 07
Step H — What the marker is looking for
On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.
Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.
5. The answer
19 as large
Copy onto your answer sheet — in this order
Answer: 19 as large
6. Check it like a marker
F is proportional to 1r², so ×3 in r means ×19 in F.
7. A trap first-timers fall into
13 as large
20 · 3 Marks
F=IℓB, I=3 A, ℓ=0.4 m, B=0.5 T, 90°
How we got there
Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.
Explain in another language · 11
1. What is the question asking?
Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: F=IℓB, I=3 A, ℓ=0.4 m, B=0.5 T, 90°
Before any working — hunt first
Given
Numbers and units already in the sentence: 3 A · 0.4 m · 0.5 T · 90°. Copy each one into a column. A name without a number is not given.
Missing
After you copy the given, the letter that still has no number is missing. The paper is pointing at: 5 T, 90°. Circle that word — that is the missing variable.
Find
We are required to find: 5 T, 90°. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate
What we need to calculate: 0. Then substitute the given, one line at a time, to get 5 T, 90°.
In other words — as if you have never seen this before
0.6 N
2. What do we already know?
Copy these onto the left of your page, one per line, with units: 3 A · 0.4 m · 0.5 T · 90°. Mixing cm with m, or minutes with seconds, loses a method mark.
3. Which method — and why this one?
0.6 N
4. Step-by-step working
01 / 08
Step A — Read the question twice
Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
02 / 08
Step A2 — Hunt: Given, Missing, Find, Calculate
Given: Numbers and units already in the sentence: 3 A · 0.4 m · 0.5 T · 90°. Copy each one into a column. A name without a number is not given.
Missing: After you copy the given, the letter that still has no number is missing. The paper is pointing at: 5 T, 90°. Circle that word — that is the missing variable.
Find: We are required to find: 5 T, 90°. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate: What we need to calculate: 0. Then substitute the given, one line at a time, to get 5 T, 90°.
Why this step: Do not name the letters yet. First hunt: what already has a number (Given), what has no number (Missing), the word the paper wants (Find), and which formula still contains the missing letter (Calculate).
03 / 08
Step B — Write the given in a column
Copy these onto the left of your page, one per line, with units: 3 A · 0.4 m · 0.5 T · 90°. Mixing cm with m, or minutes with seconds, loses a method mark.
Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.
04 / 08
Step C — Name the method in words
0.6 N
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
05 / 08
Reason
3×0.4×0.5=0.6.
Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.
06 / 08
Step G — Sense-check the size
Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.
Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.
07 / 08
Step F — Box the answer with its unit
0.6 N
Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.
08 / 08
Step H — What the marker is looking for
On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.
Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.
5. The answer
0.6 N
Copy onto your answer sheet — in this order
Answer: 0.6 N
6. Check it like a marker
Does your answer appear as one of the options? Do the units match what was asked (m, N, J, °)? If you put the number back into the original equation, does it still hold? Estimate: is the size sensible?
7. A trap first-timers fall into
First-timers often grab the first formula they remember, mix units (cm with m, minutes with seconds), or drop a minus sign. Write the formula in words first: “this equals that, because…”
21 · 3 Marks
n=1.33 (water) into air. sin c=
How we got there
Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.
Explain in another language · 11
1. What is the question asking?
Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: n = 1.33 (water) into air. sin c =
Before any working — hunt first
Given
Numbers and units already in the sentence: 1.33. Copy each one into a column. A name without a number is not given.
Missing
After you copy the given, the letter that still has no number is missing. The paper is pointing at: sin c =. Circle that word — that is the missing variable.
Find
We are required to find: sin c =. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate
What we need to calculate: 11. Then substitute the given, one line at a time, to get sin c =.
In other words — as if you have never seen this before
11.33
2. What do we already know?
Copy these onto the left of your page, one per line, with units: 1.33. Mixing cm with m, or minutes with seconds, loses a method mark.
3. Which method — and why this one?
11.33
4. Step-by-step working
01 / 08
Step A — Read the question twice
Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
02 / 08
Step A2 — Hunt: Given, Missing, Find, Calculate
Given: Numbers and units already in the sentence: 1.33. Copy each one into a column. A name without a number is not given.
Missing: After you copy the given, the letter that still has no number is missing. The paper is pointing at: sin c =. Circle that word — that is the missing variable.
Find: We are required to find: sin c =. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate: What we need to calculate: 11. Then substitute the given, one line at a time, to get sin c =.
Why this step: Do not name the letters yet. First hunt: what already has a number (Given), what has no number (Missing), the word the paper wants (Find), and which formula still contains the missing letter (Calculate).
03 / 08
Step B — Write the given in a column
Copy these onto the left of your page, one per line, with units: 1.33. Mixing cm with m, or minutes with seconds, loses a method mark.
Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.
04 / 08
Step C — Name the method in words
11.33
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
05 / 08
Working
sin c = n₂ / n₁ = 11.33 when light goes denser → rarer. That is the critical-angle setup for TIR.
Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.
06 / 08
Step G — Sense-check the size
Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.
Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.
07 / 08
Step F — Box the answer with its unit
11.33
Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.
08 / 08
Step H — What the marker is looking for
On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.
Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.
5. The answer
11.33
Copy onto your answer sheet — in this order
Answer: 11.33
6. Check it like a marker
Does your answer appear as one of the options? Do the units match what was asked (m, N, J, °)? If you put the number back into the original equation, does it still hold? Estimate: is the size sensible?
7. A trap first-timers fall into
First-timers often grab the first formula they remember, mix units (cm with m, minutes with seconds), or drop a minus sign. Write the formula in words first: “this equals that, because…”
22 · 2 Marks
m = 8 kg and a = 3 m·s⁻². F_net =
Notes: m = 8 kg and a = 3 m·s⁻². F_net =
How we got there
Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.
Explain in another language · 11
1. What is the question asking?
Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: m = 8 kg and a = 3 m·s⁻². F_net =
Before any working — hunt first
Given
Numbers and units already in the sentence: 8 kg · 3 m·s⁻². Copy each one into a column. A name without a number is not given.
Missing
After you copy the given, the letter that still has no number is missing. The paper is pointing at: F_net =. Circle that word — that is the missing variable.
Find
We are required to find: F_net =. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate
What we need to calculate: F_net = ma = 24 N. Then substitute the given, one line at a time, to get F_net =.
In other words — as if you have never seen this before
Fnet=ma=24 N.
2. What do we already know?
m = 8 kg and a = 3 m·s⁻². F_net =
3. Which method — and why this one?
Fnet=ma=24 N.
4. Step-by-step working
01 / 08
Step A — Read the question twice
Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
02 / 08
Step A2 — Hunt: Given, Missing, Find, Calculate
Given: Numbers and units already in the sentence: 8 kg · 3 m·s⁻². Copy each one into a column. A name without a number is not given.
Missing: After you copy the given, the letter that still has no number is missing. The paper is pointing at: F_net =. Circle that word — that is the missing variable.
Find: We are required to find: F_net =. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate: What we need to calculate: F_net = ma = 24 N. Then substitute the given, one line at a time, to get F_net =.
Why this step: Do not name the letters yet. First hunt: what already has a number (Given), what has no number (Missing), the word the paper wants (Find), and which formula still contains the missing letter (Calculate).
03 / 08
Step B — Write the given in a column
m = 8 kg and a = 3 m·s⁻². F_net =
Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.
04 / 08
Step C — Name the method in words
Fnet=ma=24 N.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
05 / 08
Working
Fnet=ma=24 N.
Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.
06 / 08
Step G — Sense-check the size
Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.
Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.
07 / 08
Step F — Box the answer with its unit
24 N
Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.
08 / 08
Step H — What the marker is looking for
On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.
Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.
5. The answer
24 N
Copy onto your answer sheet — in this order
Answer: 24 N
6. Check it like a marker
Fnet=ma=24 N.
7. A trap first-timers fall into
11 N
23 · 2 Marks
A 1.5 kW heater runs for 4 h. Energy used?
How we got there
Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.
Explain in another language · 11
1. What is the question asking?
Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: A 1.5 kW heater runs for 4 h. Energy used?
Before any working — hunt first
Given
Numbers and units already in the sentence: 1.5 kW · 4 h. Copy each one into a column. A name without a number is not given.
Missing
After you copy the given, the letter that still has no number is missing. The paper is pointing at: Energy used. Circle that word — that is the missing variable.
Find
We are required to find: Energy used. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate
What we need to calculate: W = Pt = 1. Then substitute the given, one line at a time, to get Energy used.
In other words — as if you have never seen this before
W=Pt=1.5 kW×4 h=6 kWh (= 2.16 × 10⁷ J).
2. What do we already know?
Copy these onto the left of your page, one per line, with units: 1.5 kW · 4 h. Mixing cm with m, or minutes with seconds, loses a method mark.
3. Which method — and why this one?
W=Pt=1.5 kW×4 h=6 kWh (= 2.16 × 10⁷ J).
4. Step-by-step working
01 / 08
Step A — Read the question twice
Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
02 / 08
Step A2 — Hunt: Given, Missing, Find, Calculate
Given: Numbers and units already in the sentence: 1.5 kW · 4 h. Copy each one into a column. A name without a number is not given.
Missing: After you copy the given, the letter that still has no number is missing. The paper is pointing at: Energy used. Circle that word — that is the missing variable.
Find: We are required to find: Energy used. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate: What we need to calculate: W = Pt = 1. Then substitute the given, one line at a time, to get Energy used.
Why this step: Do not name the letters yet. First hunt: what already has a number (Given), what has no number (Missing), the word the paper wants (Find), and which formula still contains the missing letter (Calculate).
03 / 08
Step B — Write the given in a column
Copy these onto the left of your page, one per line, with units: 1.5 kW · 4 h. Mixing cm with m, or minutes with seconds, loses a method mark.
Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.
04 / 08
Step C — Name the method in words
W=Pt=1.5 kW×4 h=6 kWh (= 2.16 × 10⁷ J).
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
05 / 08
Working
W=Pt=1.5 kW×4 h=6 kWh (= 2.16 × 10⁷ J).
Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.
06 / 08
Step G — Sense-check the size
Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.
Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.
07 / 08
Step F — Box the answer with its unit
6 kWh
Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.
08 / 08
Step H — What the marker is looking for
On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.
Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.
5. The answer
6 kWh
Copy onto your answer sheet — in this order
Answer: 6 kWh
6. Check it like a marker
Does your answer appear as one of the options? Do the units match what was asked (m, N, J, °)? If you put the number back into the original equation, does it still hold? Estimate: is the size sensible?
7. A trap first-timers fall into
First-timers often grab the first formula they remember, mix units (cm with m, minutes with seconds), or drop a minus sign. Write the formula in words first: “this equals that, because…”
24 · 2 Marks · Friction
m = 4 kg. Horizontal F = 20 N, friction 4 N. a?
Friction
Formulas
fs ≤ μs N
Static friction (maximum at the point of slipping)
fk=μk N
Kinetic friction
Notes: m = 4 kg. Applied 20 N. Friction 4 N opposite. Unknown: a.
How we got there
Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.
Explain in another language · 11
1. What is the question asking?
Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: m = 4 kg. Horizontal F = 20 N, friction 4 N. a?
Before any working — hunt first
Given
Numbers and units already in the sentence: 4 kg · 20 N · 4 N. Copy each one into a column. A name without a number is not given.
Missing
After you copy the given, the letter that still has no number is missing. The paper is pointing at: a. Circle that word — that is the missing variable.
Find
We are required to find: a. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate
Write F_net = 16 N with empty letters. Cross out every letter that already has a number. Calculate the letter that is still standing — that gives a.
In other words — as if you have never seen this before
F_net = applied − friction, then a = Fnetm. Draw arrows first.
2. What do we already know?
m = 4 kg. Applied 20 N. Friction 4 N opposite. Unknown: a.
3. Which method — and why this one?
F_net = applied − friction, then a = Fnetm. Draw arrows first.
4. Step-by-step working
01 / 05
Net force
Fnet=20−4=16 N forwards.
Fnet=16 N
Why this step: One job per line so you can find a slip, and so a marker can follow the marks.
02 / 05
Newton 2
a=Fnetm=164=4 m·s⁻².
a=4 ms²
Why this step: Write the formula before numbers. The memo awards a method mark even if a digit slips later.
03 / 05
Step G — Sense-check the size
Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.
Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.
04 / 05
Step F — Box the answer with its unit
4 ms²
Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.
05 / 05
Step H — What the marker is looking for
On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.
Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.
5. The answer
4 ms²
Copy onto your answer sheet — in this order
Formula: Fnet=16 N
Answer: 4 ms²
6. Check it like a marker
16 N on 4 kg really is 4 m·s⁻². Units: Nkg=m·s⁻².
7. A trap first-timers fall into
Using 204=5 ignores friction. The paper gave 4 N for a reason.
25 · 2 Marks
n=1.5 into air. sin c=
How we got there
Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.
Explain in another language · 11
1. What is the question asking?
Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: n = 1.5 into air. sin c =
Before any working — hunt first
Given
Numbers and units already in the sentence: 1.5 into. Copy each one into a column. A name without a number is not given.
Missing
After you copy the given, the letter that still has no number is missing. The paper is pointing at: sin c =. Circle that word — that is the missing variable.
Find
We are required to find: sin c =. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate
What we need to calculate: sin c = n₂/n₁ = 11. Then substitute the given, one line at a time, to get sin c =.
In other words — as if you have never seen this before
sin c=n₂n₁=11.5.
2. What do we already know?
Copy these onto the left of your page, one per line, with units: 1.5 into. Mixing cm with m, or minutes with seconds, loses a method mark.
3. Which method — and why this one?
sin c=n₂n₁=11.5.
4. Step-by-step working
01 / 08
Step A — Read the question twice
Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
02 / 08
Step A2 — Hunt: Given, Missing, Find, Calculate
Given: Numbers and units already in the sentence: 1.5 into. Copy each one into a column. A name without a number is not given.
Missing: After you copy the given, the letter that still has no number is missing. The paper is pointing at: sin c =. Circle that word — that is the missing variable.
Find: We are required to find: sin c =. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate: What we need to calculate: sin c = n₂/n₁ = 11. Then substitute the given, one line at a time, to get sin c =.
Why this step: Do not name the letters yet. First hunt: what already has a number (Given), what has no number (Missing), the word the paper wants (Find), and which formula still contains the missing letter (Calculate).
03 / 08
Step B — Write the given in a column
Copy these onto the left of your page, one per line, with units: 1.5 into. Mixing cm with m, or minutes with seconds, loses a method mark.
Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.
04 / 08
Step C — Name the method in words
sin c=n₂n₁=11.5.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
05 / 08
Working
sin c=n₂n₁=11.5.
Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.
06 / 08
Step G — Sense-check the size
Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.
Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.
07 / 08
Step F — Box the answer with its unit
11.5
Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.
08 / 08
Step H — What the marker is looking for
On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.
Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.
5. The answer
11.5
Copy onto your answer sheet — in this order
Answer: 11.5
6. Check it like a marker
Does your answer appear as one of the options? Do the units match what was asked (m, N, J, °)? If you put the number back into the original equation, does it still hold? Estimate: is the size sensible?
7. A trap first-timers fall into
First-timers often grab the first formula they remember, mix units (cm with m, minutes with seconds), or drop a minus sign. Write the formula in words first: “this equals that, because…”
26 · 2 Marks · Coulomb’s law & fields
If r doubles, Coulomb F becomes
Coulomb’s law & fields
Formulas
F=k Q₁ Q₂r²
Coulomb’s law
How we got there
Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.
Explain in another language · 11
1. What is the question asking?
Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: If r doubles, Coulomb F becomes
Before any working — hunt first
Given
Numbers and units already in the sentence: no numbers yet — only a name, a diagram, or a worded unknown. Copy each one into a column. A name without a number is not given.
Missing
After you copy the given, the letter that still has no number is missing. The paper is pointing at: If r doubles, Coulomb F becomes. Circle that word — that is the missing variable.
Find
We are required to find: If r doubles, Coulomb F becomes. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate
What we need to calculate: a quarter. Then substitute the given, one line at a time, to get If r doubles, Coulomb F becomes.
In other words — as if you have never seen this before
a quarter
2. What do we already know?
Copy these onto the left of your page, one per line, with units: every number and its unit in the sentence. Mixing cm with m, or minutes with seconds, loses a method mark.
3. Which method — and why this one?
a quarter
4. Step-by-step working
01 / 08
Step A — Read the question twice
Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
02 / 08
Step A2 — Hunt: Given, Missing, Find, Calculate
Given: Numbers and units already in the sentence: no numbers yet — only a name, a diagram, or a worded unknown. Copy each one into a column. A name without a number is not given.
Missing: After you copy the given, the letter that still has no number is missing. The paper is pointing at: If r doubles, Coulomb F becomes. Circle that word — that is the missing variable.
Find: We are required to find: If r doubles, Coulomb F becomes. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate: What we need to calculate: a quarter. Then substitute the given, one line at a time, to get If r doubles, Coulomb F becomes.
Why this step: Do not name the letters yet. First hunt: what already has a number (Given), what has no number (Missing), the word the paper wants (Find), and which formula still contains the missing letter (Calculate).
03 / 08
Step B — Write the given in a column
Copy these onto the left of your page, one per line, with units: every number and its unit in the sentence. Mixing cm with m, or minutes with seconds, loses a method mark.
Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.
04 / 08
Step C — Name the method in words
a quarter
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
05 / 08
Working
F ∝ 1r². Double r → 2² = 4 times smaller → a quarter. Square the factor.
Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.
06 / 08
Step G — Sense-check the size
Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.
Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.
07 / 08
Step F — Box the answer with its unit
a quarter
Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.
08 / 08
Step H — What the marker is looking for
On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.
Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.
5. The answer
a quarter
Copy onto your answer sheet — in this order
Answer: a quarter
6. Check it like a marker
Does your answer appear as one of the options? Do the units match what was asked (m, N, J, °)? If you put the number back into the original equation, does it still hold? Estimate: is the size sensible?
7. A trap first-timers fall into
First-timers often grab the first formula they remember, mix units (cm with m, minutes with seconds), or drop a minus sign. Write the formula in words first: “this equals that, because…”
27 · 3 Marks
g on Earth 9.8, on Moon ≈ 1.6. Mass of 10 kg on Moon?
Notes: m = 10 kg on Earth. Moved to the Moon.
How we got there
Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.
Explain in another language · 11
1. What is the question asking?
Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: g on Earth 9.8, on Moon ≈ 1.6. Mass of 10 kg on Moon?
Before any working — hunt first
Given
Numbers and units already in the sentence: 9.8 · 1.6 · 10 kg. Copy each one into a column. A name without a number is not given.
Missing
After you copy the given, the letter that still has no number is missing. The paper is pointing at: Mass of 10 kg on Moon. Circle that word — that is the missing variable.
Find
We are required to find: Mass of 10 kg on Moon. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate
Write m = 10 kg with empty letters. Cross out every letter that already has a number. Calculate the letter that is still standing — that gives Mass of 10 kg on Moon.
In other words — as if you have never seen this before
Mass is the amount of matter. It does not change. Weight does.
2. What do we already know?
m = 10 kg on Earth. Moved to the Moon.
3. Which method — and why this one?
Mass is the amount of matter. It does not change. Weight does.
4. Step-by-step working
01 / 08
Step A — Read the question twice
Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
02 / 08
Step A2 — Hunt: Given, Missing, Find, Calculate
Given: Numbers and units already in the sentence: 9.8 · 1.6 · 10 kg. Copy each one into a column. A name without a number is not given.
Missing: After you copy the given, the letter that still has no number is missing. The paper is pointing at: Mass of 10 kg on Moon. Circle that word — that is the missing variable.
Find: We are required to find: Mass of 10 kg on Moon. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate: Write m = 10 kg with empty letters. Cross out every letter that already has a number. Calculate the letter that is still standing — that gives Mass of 10 kg on Moon.
Why this step: Do not name the letters yet. First hunt: what already has a number (Given), what has no number (Missing), the word the paper wants (Find), and which formula still contains the missing letter (Calculate).
03 / 08
Step B — Write the given in a column
m = 10 kg on Earth. Moved to the Moon.
Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.
04 / 08
Step C — Name the method in words
Mass is the amount of matter. It does not change. Weight does.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
05 / 08
Mass is invariant
mmoon=10 kg. Weight would be 16 N.
m=10 kg
Why this step: Write the formula before numbers. The memo awards a method mark even if a digit slips later.
06 / 08
Step G — Sense-check the size
Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.
Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.
07 / 08
Step F — Box the answer with its unit
10 kg
Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.
08 / 08
Step H — What the marker is looking for
On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.
Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.
5. The answer
10 kg
Copy onto your answer sheet — in this order
Formula: m=10 kg
Answer: 10 kg
6. Check it like a marker
W_moon = 10 × 1.6 = 16 N. That is weight, not mass.
7. A trap first-timers fall into
1.6 kg confuses g with mass. 16 N is weight. The asking-word is mass.
28 · 2 Marks · Refraction & TIR
Total internal reflection happens when light goes
Refraction & TIR
Formulas
n₁ sinθ₁=n₂ sinθ₂
Snell’s law
Notes: Total internal reflection happens when light goes
How we got there
Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.
Explain in another language · 11
1. What is the question asking?
Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: Total internal reflection happens when light goes
In other words — as if you have never seen this before
Both conditions are required: denser to rarer, and i > c.
2. What do we already know?
Total internal reflection happens when light goes
3. Which method — and why this one?
Both conditions are required: denser to rarer, and i > c.
4. Step-by-step working
01 / 07
Step A — Read the question twice
Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
02 / 07
Step B — Write the given in a column
Total internal reflection happens when light goes
Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.
03 / 07
Step C — Name the method in words
Both conditions are required: denser to rarer, and i > c.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
04 / 07
Working
Both conditions are required: denser to rarer, and i > c.
Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.
05 / 07
Step G — Sense-check the size
Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.
Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.
06 / 07
Step F — Box the answer with its unit
from denser to rarer, with i greater than the critical angle
Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.
07 / 07
Step H — What the marker is looking for
On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.
Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.
5. The answer
from denser to rarer, with i greater than the critical angle
Copy onto your answer sheet — in this order
Answer: from denser to rarer, with i greater than the critical angle
6. Check it like a marker
Both conditions are required: denser to rarer, and i > c.
7. A trap first-timers fall into
from rarer to denser at any angle
29 · 3 Marks
n=1.5, nair=1. sin c=
How we got there
Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.
Explain in another language · 11
1. What is the question asking?
Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: n=1.5, n_air=1. sin c =
Before any working — hunt first
Given
Numbers and units already in the sentence: 1.5 · 1. Copy each one into a column. A name without a number is not given.
Missing
After you copy the given, the letter that still has no number is missing. The paper is pointing at: sin c =. Circle that word — that is the missing variable.
Find
We are required to find: sin c =. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate
What we need to calculate: 23. Then substitute the given, one line at a time, to get sin c =.
In other words — as if you have never seen this before
23
2. What do we already know?
Copy these onto the left of your page, one per line, with units: 1.5 · 1. Mixing cm with m, or minutes with seconds, loses a method mark.
3. Which method — and why this one?
23
4. Step-by-step working
01 / 08
Step A — Read the question twice
Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
02 / 08
Step A2 — Hunt: Given, Missing, Find, Calculate
Given: Numbers and units already in the sentence: 1.5 · 1. Copy each one into a column. A name without a number is not given.
Missing: After you copy the given, the letter that still has no number is missing. The paper is pointing at: sin c =. Circle that word — that is the missing variable.
Find: We are required to find: sin c =. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate: What we need to calculate: 23. Then substitute the given, one line at a time, to get sin c =.
Why this step: Do not name the letters yet. First hunt: what already has a number (Given), what has no number (Missing), the word the paper wants (Find), and which formula still contains the missing letter (Calculate).
03 / 08
Step B — Write the given in a column
Copy these onto the left of your page, one per line, with units: 1.5 · 1. Mixing cm with m, or minutes with seconds, loses a method mark.
Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.
04 / 08
Step C — Name the method in words
23
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
05 / 08
Reason
sin c=11.5.
Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.
06 / 08
Step G — Sense-check the size
Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.
Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.
07 / 08
Step F — Box the answer with its unit
23
Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.
08 / 08
Step H — What the marker is looking for
On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.
Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.
5. The answer
23
Copy onto your answer sheet — in this order
Answer: 23
6. Check it like a marker
Does your answer appear as one of the options? Do the units match what was asked (m, N, J, °)? If you put the number back into the original equation, does it still hold? Estimate: is the size sensible?
7. A trap first-timers fall into
First-timers often grab the first formula they remember, mix units (cm with m, minutes with seconds), or drop a minus sign. Write the formula in words first: “this equals that, because…”
30 · 4 Marks · Friction
On a 30° frictionless slope, acceleration down the slope is
Friction
Formulas
fs ≤ μs N
Static friction (maximum at the point of slipping)
fk=μk N
Kinetic friction
How we got there
Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.
Explain in another language · 11
1. What is the question asking?
Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: On a 30° frictionless slope, acceleration down the slope is
In other words — as if you have never seen this before
Component of weight down the slope.
2. What do we already know?
Copy these onto the left of your page, one per line, with units: 30°. Mixing cm with m, or minutes with seconds, loses a method mark.
3. Which method — and why this one?
Component of weight down the slope.
4. Step-by-step working
01 / 07
Step A — Read the question twice
Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
02 / 07
Step B — Write the given in a column
Copy these onto the left of your page, one per line, with units: 30°. Mixing cm with m, or minutes with seconds, loses a method mark.
Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.
03 / 07
Step C — Name the method in words
Component of weight down the slope.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
04 / 07
Working
Component of weight down the slope.
Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.
05 / 07
Step G — Sense-check the size
Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.
Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.
06 / 07
Step F — Box the answer with its unit
g sin 30°
Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.
07 / 07
Step H — What the marker is looking for
On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.
Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.
5. The answer
g sin 30°
Copy onto your answer sheet — in this order
Answer: g sin 30°
6. Check it like a marker
Does your answer appear as one of the options? Do the units match what was asked (m, N, J, °)? If you put the number back into the original equation, does it still hold? Estimate: is the size sensible?
7. A trap first-timers fall into
First-timers often grab the first formula they remember, mix units (cm with m, minutes with seconds), or drop a minus sign. Write the formula in words first: “this equals that, because…”