Notes: No numbers. Definition question from the mechanics section.
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 equals
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: Impulse equals. Circle that word — that is the missing variable.
Find
We are required to find: Impulse equals. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate
Write FΔt = Δp with empty letters. Cross out every letter that already has a number. Calculate the letter that is still standing — that gives Impulse equals.
In other words — as if you have never seen this before
Impulse J = FΔt = Δp = m(v_f − v_i). It is a vector.
2. What do we already know?
No numbers. Definition question from the mechanics section.
3. Which method — and why this one?
Impulse J = FΔt = Δp = m(v_f − v_i). It is a vector.
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: Impulse equals. Circle that word — that is the missing variable.
Find: We are required to find: Impulse equals. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate: Write FΔt = Δp with empty letters. Cross out every letter that already has a number. Calculate the letter that is still standing — that gives Impulse equals.
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
No numbers. Definition question from the mechanics section.
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 J = FΔt = Δp = m(v_f − v_i). It is a vector.
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
Quote the law
Impulse is the change in momentum, FΔt = Δp.
FΔt=Δp
Why this step: Write the formula before numbers. The memo awards a method mark for the law 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
change in momentum
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
change in momentum
Copy onto your answer sheet — in this order
Formula: FΔt=Δp
Answer: change in momentum
6. Check it like a marker
Units: N·s = kg·m·s⁻¹, same as momentum. Matches.
7. A trap first-timers fall into
Mass × velocity is momentum p, not impulse. Impulse is the change in p.
1.2 · 12 Marks
Thrown up at 19.6 m·s⁻¹. Time to top? (g=9.8)
Notes: v_i = +19.6 m·s⁻¹ up. v_f = 0 at the top. a = −9.8 m·s⁻².
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: Thrown up at 19.6 m·s⁻¹. Time to top? (g=9.8)
Before any working — hunt first
Given
Numbers and units already in the sentence: 19.6 m·s⁻¹ · 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
Write v_f = v_i + at with empty letters. Cross out every letter that already has a number. Calculate the letter that is still standing — that gives 8).
In other words — as if you have never seen this before
v_f = v_i + a t. At the top the velocity is instantaneously zero.
2. What do we already know?
v_i = +19.6 m·s⁻¹ up. v_f = 0 at the top. a = −9.8 m·s⁻².
3. Which method — and why this one?
v_f = v_i + a t. At the top the velocity is instantaneously zero.
4. Step-by-step working
01 / 05
Write the equation
0=19.6+(−9.8)t.
vf=vi+at
Why this step: Write the formula before numbers. The memo awards a method mark for the law even if a digit slips later.
02 / 05
Solve
9.8 t=19.6→t=2 s.
t=2 s
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
2 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.
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
2 s
Copy onto your answer sheet — in this order
Formula: vf=vi+at
Answer: 2 s
6. Check it like a marker
From rest it would take 2 s to reach 19.6 m·s⁻¹ down. Time up equals time down.
7. A trap first-timers fall into
Do not use v² = u²+2aΔy here unless they ask for height. Sign of g: take upward positive so a is negative.
2.1 · 14 Marks
Np=200, Ns=50, Vp=240 V. Vs=
Notes: Primary turns 200, secondary 50, primary voltage 240 V. Step-down.
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: Np=200, Ns=50, Vp=240 V. Vs =
Before any working — hunt first
Given
Numbers and units already in the sentence: 200 · 50 · 240 V. 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: Vs =. Circle that word — that is the missing variable.
Find
We are required to find: Vs =. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate
Write VsVp=NsNp with empty letters. Cross out every letter that already has a number. Calculate the letter that is still standing — that gives Vs =.
In other words — as if you have never seen this before
VsVp=NsNp for an ideal transformer.
2. What do we already know?
Primary turns 200, secondary 50, primary voltage 240 V. Step-down.
3. Which method — and why this one?
VsVp=NsNp for an ideal transformer.
4. Step-by-step working
01 / 05
Write the ratio
VsVp=NsNp.
VsVp=NsNp
Why this step: Write the formula before numbers. The memo awards a method mark for the law even if a digit slips later.
02 / 05
Substitute
Vs=240×50200=240×0.25=60 V.
Vs=60 V
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
60 V
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.
Do not invert the ratio (that gives 960 V, a step-up). Count Ns on top with Vs.
2.2 · 14 Marks · Emission, absorption & photoelectric
hf < W₀. Photoelectrons
Emission, absorption & photoelectric
Formulas
E=h fW₀=h f₀Kmax=h f−W₀
Photon energy and work function
Notes: Photon energy hf is less than the work function W₀.
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: hf < W₀. Photoelectrons
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: Photoelectrons. Circle that word — that is the missing variable.
Find
We are required to find: Photoelectrons. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate
Write E_k = hf − W₀ with empty letters. Cross out every letter that already has a number. Calculate the letter that is still standing — that gives Photoelectrons.
In other words — as if you have never seen this before
Einstein: E_k(max) = hf − W₀. If hf < W₀ the right side is negative, which is impossible — no emission.
2. What do we already know?
Photon energy hf is less than the work function W₀.
3. Which method — and why this one?
Einstein: E_k(max) = hf − W₀. If hf < W₀ the right side is negative, which is impossible — no emission.
4. Step-by-step working
01 / 05
Write Einstein’s equation
Ek(max)=hf−W₀. Need hf ≥ W₀.
Ek=hf−W₀
Why this step: Write the formula before numbers. The memo awards a method mark for the law even if a digit slips later.
02 / 05
Interpret the inequality
hf < W₀ means every photon is short of the work function. Intensity cannot help — each photon acts alone.
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
are not emitted
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
are not emitted
Copy onto your answer sheet — in this order
Formula: Ek=hf−W₀
Answer: are not emitted
6. Check it like a marker
Threshold frequency f₀ = W₀/h is a hard cut-off. Below it, zero photoelectrons.
7. A trap first-timers fall into
Do not say “emitted if intensity is high”. Intensity is number of photons, not energy per photon.
5 · 2 Marks
SA mains RMS voltage 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: SA mains RMS voltage 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: SA mains RMS voltage is. Circle that word — that is the missing variable.
Find
We are required to find: SA mains RMS voltage is. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate
What we need to calculate: NSC uses 230 V RMS. Then substitute the given, one line at a time, to get SA mains RMS voltage is.
In other words — as if you have never seen this before
NSC uses 230 V RMS. Vmax=230√2 ≈ 325 V.
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?
NSC uses 230 V RMS. Vmax=230√2 ≈ 325 V.
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: SA mains RMS voltage is. Circle that word — that is the missing variable.
Find: We are required to find: SA mains RMS voltage is. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate: What we need to calculate: NSC uses 230 V RMS. Then substitute the given, one line at a time, to get SA mains RMS voltage 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
NSC uses 230 V RMS. Vmax=230√2 ≈ 325 V.
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
NSC uses 230 V RMS. Vmax=230√2 ≈ 325 V.
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
230 V
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
230 V
Copy onto your answer sheet — in this order
Answer: 230 V
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…”
6 · 3 Marks
Time of flight for a throw up and back, v_i=19.6 m·s⁻¹ (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: Time of flight for a throw up and back, v_i=19.6 m·s⁻¹ (g=9.8)
Before any working — hunt first
Given
Numbers and units already in the sentence: 19.6 m·s⁻¹ · 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: Up 2 s, down 2 s. Then substitute the given, one line at a time, to get 8).
In other words — as if you have never seen this before
Up 2 s, down 2 s.
2. What do we already know?
Copy these onto the left of your page, one per line, with units: 19.6 m·s⁻¹ · 9.8. Mixing cm with m, or minutes with seconds, loses a method mark.
3. Which method — and why this one?
Up 2 s, down 2 s.
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: 19.6 m·s⁻¹ · 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: Up 2 s, down 2 s. 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: 19.6 m·s⁻¹ · 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
Up 2 s, down 2 s.
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
Up 2 s, down 2 s.
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
4 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
4 s
Copy onto your answer sheet — in this order
Answer: 4 s
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
Magnetic flux Φ=
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: Magnetic flux Φ =
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: Magnetic flux Φ =. Circle that word — that is the missing variable.
Find
We are required to find: Magnetic flux Φ =. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate
What we need to calculate: θ between B and the normal to the area. Then substitute the given, one line at a time, to get Magnetic flux Φ =.
In other words — as if you have never seen this before
θ between B and the normal to the area.
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?
θ between B and the normal to the area.
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: Magnetic flux Φ =. Circle that word — that is the missing variable.
Find: We are required to find: Magnetic flux Φ =. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate: What we need to calculate: θ between B and the normal to the area. Then substitute the given, one line at a time, to get Magnetic flux Φ =.
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
θ between B and the normal to the area.
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
θ between B and the normal to the area.
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
B A cos θ
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
B A cos θ
Copy onto your answer sheet — in this order
Answer: B A cos θ
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
E=hf. f=6×10¹⁴ Hz, h=6.6×10⁻³⁴. E?
Notes: f = 6×10¹⁴ Hz. h = 6.6×10⁻³⁴ J·s. Unknown: photon energy 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: E = hf. f = 6×10¹⁴ Hz, h = 6.6×10⁻³⁴. E?
Before any working — hunt first
Given
Numbers and units already in the sentence: 6 · 10¹ · 6.6 · 10⁻³. 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
Write E = hf with empty letters. Cross out every letter that already has a number. Calculate the letter that is still standing — that gives E.
In other words — as if you have never seen this before
E = hf. Do not divide. Keep scientific notation.
2. What do we already know?
f = 6×10¹⁴ Hz. h = 6.6×10⁻³⁴ J·s. Unknown: photon energy E.
3. Which method — and why this one?
E = hf. Do not divide. Keep scientific notation.
4. Step-by-step working
01 / 05
Write Planck
E=h f.
E=hf
Why this step: Write the formula before numbers. The memo awards a method mark even if a digit slips later.
02 / 05
Multiply
6.6×10⁻³⁴×6×10¹⁴=39.6×10⁻²⁰=3.96×10⁻¹⁹ ≈ 4.0×10⁻¹⁹ J.
E=4.0×10⁻¹⁹ J
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
4.0×10⁻¹⁹ 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
4.0×10⁻¹⁹ J
Copy onto your answer sheet — in this order
Formula: E=hf
Answer: 4.0×10⁻¹⁹ J
6. Check it like a marker
Order of magnitude 10⁻¹⁹ J is a visible photon. 10⁻⁴⁸ would be nonsense.
7. A trap first-timers fall into
E = hf is the reciprocal. The paper wrote E = hf on the formula sheet.
9 · 3 Marks · Work, energy & power
If hf < W₀, photoelectrons
Formulas
W=F Δx cosθ
Work
P=WΔt=F v
Power
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 hf < W₀, photoelectrons
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 hf < W₀, photoelectrons. Circle that word — that is the missing variable.
Find
We are required to find: If hf < W₀, photoelectrons. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate
What we need to calculate: Photon energy must at least equal the work function. Then substitute the given, one line at a time, to get If hf < W₀, photoelectrons.
In other words — as if you have never seen this before
Photon energy must at least equal the work function.
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?
Photon energy must at least equal the work function.
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 hf < W₀, photoelectrons. Circle that word — that is the missing variable.
Find: We are required to find: If hf < W₀, photoelectrons. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate: What we need to calculate: Photon energy must at least equal the work function. Then substitute the given, one line at a time, to get If hf < W₀, photoelectrons.
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
Photon energy must at least equal the work function.
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
Photon energy must at least equal the work function.
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
are not emitted
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
are not emitted
Copy onto your answer sheet — in this order
Answer: are not emitted
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
A listener moving towards a stationary source hears
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 listener moving towards a stationary source hears
In other words — as if you have never seen this before
Plus in the numerator.
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?
Plus in the numerator.
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: 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.
03 / 07
Step C — Name the method in words
Plus in the numerator.
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
Plus in the numerator.
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
higher f
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
higher f
Copy onto your answer sheet — in this order
Answer: higher f
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 · Vertical projectile motion
At the top of a vertical throw, velocity is
Vertical projectile motion
Formulas
Δy=vi Δt+½ a (Δt)²
Vertical 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: At the top of a vertical throw, velocity is
In other words — as if you have never seen this before
v=0 for an instant; a is still g down.
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?
v=0 for an instant; a is still g down.
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: 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.
03 / 07
Step C — Name the method in words
v=0 for an instant; a is still g down.
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
v=0 for an instant; a is still g down.
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
zero
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
zero
Copy onto your answer sheet — in this order
Answer: zero
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…”
12 · 2 Marks
Emf is measured when
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: Emf is measured when
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: Emf is measured when. Circle that word — that is the missing variable.
Find
We are required to find: Emf is measured when. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate
What we need to calculate: ε is the open-circuit pd. Then substitute the given, one line at a time, to get Emf is measured when.
In other words — as if you have never seen this before
ε is the open-circuit pd.
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?
ε is the open-circuit pd.
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: Emf is measured when. Circle that word — that is the missing variable.
Find: We are required to find: Emf is measured when. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate: What we need to calculate: ε is the open-circuit pd. Then substitute the given, one line at a time, to get Emf is measured when.
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
ε is the open-circuit pd.
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
ε is the open-circuit pd.
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
no current is drawn (open circuit)
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
no current is drawn (open circuit)
Copy onto your answer sheet — in this order
Answer: no current is drawn (open circuit)
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 · 3 Marks
Source approaching. Observed f 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: Source approaching. 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
What we need to calculate: greater than source f. Then substitute the given, one line at a time, to get Observed f is.
In other words — as if you have never seen this before
greater than source f
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?
greater than source f
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: What we need to calculate: greater than source f. Then substitute the given, one line at a time, to get 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
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
greater than source 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.
05 / 08
Reason
Doppler blueshift of sound: higher pitch.
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
greater than source f
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
greater than source f
Copy onto your answer sheet — in this order
Answer: greater than source f
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…”
14 · 4 Marks
Source moving away. Observed f 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: Source moving away. 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
What we need to calculate: lower. Then substitute the given, one line at a time, to get Observed f is.
In other words — as if you have never seen this before
lower
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?
lower
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: What we need to calculate: lower. Then substitute the given, one line at a time, to get 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
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
lower
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
Plus in the denominator.
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
lower
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
lower
Copy onto your answer sheet — in this order
Answer: lower
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 · Work, energy & power
Work by 50 N through 4 m at 60° to displacement
Formulas
W=F Δx cosθ
Work
P=WΔt=F v
Power
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: Work by 50 N through 4 m at 60° to displacement
In other words — as if you have never seen this before
100 J
2. What do we already know?
Copy these onto the left of your page, one per line, with units: 50 N · 4 m · 60°. Mixing cm with m, or minutes with seconds, loses a method mark.
3. Which method — and why this one?
100 J
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: 50 N · 4 m · 60°. 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
100 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.
04 / 07
Reason
W=FΔx cos60=50×4×0.5=100 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.
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
100 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.
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
100 J
Copy onto your answer sheet — in this order
Answer: 100 J
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…”
16 · 4 Marks
The ± in the denominator of f_L is minus when the source
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: The ± in the denominator of f_L is minus when the source
In other words — as if you have never seen this before
Approaching source: smaller denominator, higher f.
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?
Approaching source: smaller denominator, higher 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
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.
03 / 07
Step C — Name the method in words
Approaching source: smaller denominator, higher 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
Approaching source: smaller denominator, higher 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
moves towards the listener
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
moves towards the listener
Copy onto your answer sheet — in this order
Answer: moves towards the listener
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…”
17 · 4 Marks
A transformer Np=500, Ns=100, Vp=230 V. Vs=
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 transformer Np=500, Ns=100, Vp=230 V. Vs =
Before any working — hunt first
Given
Numbers and units already in the sentence: 500 · 100 · 230 V. 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: Vs =. Circle that word — that is the missing variable.
Find
We are required to find: Vs =. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate
What we need to calculate: VsVp=NsNp. Then substitute the given, one line at a time, to get Vs =.
In other words — as if you have never seen this before
VsVp=NsNp→Vs=230×100500=46 V.
2. What do we already know?
Copy these onto the left of your page, one per line, with units: 500 · 100 · 230 V. Mixing cm with m, or minutes with seconds, loses a method mark.
3. Which method — and why this one?
VsVp=NsNp→Vs=230×100500=46 V.
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: 500 · 100 · 230 V. 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: Vs =. Circle that word — that is the missing variable.
Find: We are required to find: Vs =. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate: What we need to calculate: VsVp=NsNp. Then substitute the given, one line at a time, to get Vs =.
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: 500 · 100 · 230 V. 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
VsVp=NsNp→Vs=230×100500=46 V.
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
VsVp=NsNp→Vs=230×100500=46 V.
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
46 V
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
46 V
Copy onto your answer sheet — in this order
Answer: 46 V
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 · 2 Marks · Vertical projectile motion
A ball is thrown up at 20 ms. Time to top? (g = 10)
Vertical projectile motion
Formulas
Δy=vi Δt+½ a (Δt)²
Vertical displacement
Notes: u = 20 ms up. v = 0 at the top. a = −10 m·s⁻². Unknown: t.
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 ball is thrown up at 20 ms. Time to top? (g = 10)
Before any working — hunt first
Given
Numbers and units already in the sentence: 20 ms · 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: (g = 10). Circle that word — that is the missing variable.
Find
We are required to find: (g = 10). Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate
Write 0 = 20 − 10t with empty letters. Cross out every letter that already has a number. Calculate the letter that is still standing — that gives (g = 10).
In other words — as if you have never seen this before
v = u + at. At the top the vertical speed is zero, not the acceleration.
2. What do we already know?
u = 20 ms up. v = 0 at the top. a = −10 m·s⁻². Unknown: t.
3. Which method — and why this one?
v = u + at. At the top the vertical speed is zero, not the acceleration.
4. Step-by-step working
01 / 05
Write v = u + at
0=20+(−10)t.
0=20−10t
Why this step: Write the formula before numbers. The memo awards a method mark even if a digit slips later.
02 / 05
Solve
10t=20→t=2 s.
t=2 s
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
2 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.
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
2 s
Copy onto your answer sheet — in this order
Formula: 0=20−10t
Answer: 2 s
6. Check it like a marker
Height = ut + ½at² = 40 − 20 = 20 m. Sensible for a 20 ms throw.
7. A trap first-timers fall into
t = ug is right only if you remember a is negative. t = 20 is mixing units.
19 · 3 Marks
Gaining 2×10¹² electrons. Charge (e=1.6×10⁻¹⁹ C)
Notes: n = 2×10¹² extra electrons. e = 1.6×10⁻¹⁹ C. Electrons are negative.
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: Gaining 2×10¹² electrons. Charge (e=1.6×10⁻¹⁹ C)
Before any working — hunt first
Given
Numbers and units already in the sentence: 2 · 10¹² · 1.6 · 10⁻¹. 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: 6×10⁻¹⁹ C). Circle that word — that is the missing variable.
Find
We are required to find: 6×10⁻¹⁹ C). Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate
Write Q = n(−e) with empty letters. Cross out every letter that already has a number. Calculate the letter that is still standing — that gives 6×10⁻¹⁹ C).
In other words — as if you have never seen this before
Q = n(−e). Gaining electrons → negative charge.
2. What do we already know?
n = 2×10¹² extra electrons. e = 1.6×10⁻¹⁹ C. Electrons are negative.
3. Which method — and why this one?
Q = n(−e). Gaining electrons → negative charge.
4. Step-by-step working
01 / 05
Write Q = nq
Each electron contributes −1.6×10⁻¹⁹ C.
Q=n(−e)
Why this step: Write the formula before numbers. The memo awards a method mark for the law even if a digit slips later.
02 / 05
Multiply
Q=2×10¹²×(−1.6×10⁻¹⁹)=−3.2×10⁻⁷ C.
Q=−3.2×10⁻⁷ C
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
−3.2×10⁻⁷ 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.
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
−3.2×10⁻⁷ C
Copy onto your answer sheet — in this order
Formula: Q=n(−e)
Answer: −3.2×10⁻⁷ C
6. Check it like a marker
Powers: 10¹²×10⁻¹⁹=10⁻⁷. 2×1.6=3.2. Sign minus.
7. A trap first-timers fall into
Losing electrons would be positive. The paper said gaining.
20 · 3 Marks · Doppler effect
Source approaching a stationary listener. Observed f is
Doppler effect
Formulas
fL=fs (v ± vL)(v ± vs)
Doppler formula
Notes: Source moving towards a stationary observer. Sound in air.
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: Source approaching a stationary listener. 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_L = f_s v(v−vs) 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
Doppler: f_L = f_s (v ± vL)/(v ± v_s). Approaching source uses minus in the denominator → higher pitch.
2. What do we already know?
Source moving towards a stationary observer. Sound in air.
3. Which method — and why this one?
Doppler: f_L = f_s (v ± vL)/(v ± v_s). Approaching source uses minus in the denominator → higher pitch.
4. Step-by-step working
01 / 05
Write Doppler
Stationary listener v_L=0. Approaching source: minus under.
fL=fs v(v−vs)
Why this step: Write the formula before numbers. The memo awards a method mark for the law even if a digit slips later.
02 / 05
Read the inequality
Denominator smaller than v, so f_L > f_s. Higher pitch.
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
higher than source
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
higher than source
Copy onto your answer sheet — in this order
Formula: fL=fs v(v−vs)
Answer: higher than source
6. Check it like a marker
Ambulance coming towards you sounds higher; going away sounds lower.
7. A trap first-timers fall into
Do not swap source and listener signs. Receding would be plus in the denominator and a lower pitch.
21 · 3 Marks
Thrown up at 19.6 m·s⁻¹. Max height? (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: Thrown up at 19.6 m·s⁻¹. Max height? (g = 9.8)
Before any working — hunt first
Given
Numbers and units already in the sentence: 19.6 m·s⁻¹ · 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: 19. Then substitute the given, one line at a time, to get 8).
In other words — as if you have never seen this before
19.6 m
2. What do we already know?
Copy these onto the left of your page, one per line, with units: 19.6 m·s⁻¹ · 9.8. Mixing cm with m, or minutes with seconds, loses a method mark.
3. Which method — and why this one?
19.6 m
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: 19.6 m·s⁻¹ · 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: 19. 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: 19.6 m·s⁻¹ · 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
19.6 m
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
v² = u² + 2aΔy → 0 = (19.6)² + 2(−9.8)Δy → Δy = 19.6 m. Or v_avg × t with t = 2 s.
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
19.6 m
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
19.6 m
Copy onto your answer sheet — in this order
Answer: 19.6 m
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
Opposite charges
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: Opposite charges
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: Opposite charges. Circle that word — that is the missing variable.
Find
We are required to find: Opposite charges. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate
What we need to calculate: Unlike attract. Then substitute the given, one line at a time, to get Opposite charges.
In other words — as if you have never seen this before
Unlike attract.
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?
Unlike attract.
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: Opposite charges. Circle that word — that is the missing variable.
Find: We are required to find: Opposite charges. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate: What we need to calculate: Unlike attract. Then substitute the given, one line at a time, to get Opposite charges.
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
Unlike attract.
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
Unlike attract.
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
attract
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
attract
Copy onto your answer sheet — in this order
Answer: attract
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…”
23 · 3 Marks
230 V RMS. V_max ≈
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: 230 V RMS. V_max ≈
Before any working — hunt first
Given
Numbers and units already in the sentence: 230 V. 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: V_max ≈. Circle that word — that is the missing variable.
Find
We are required to find: V_max ≈. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate
What we need to calculate: 325 V. Then substitute the given, one line at a time, to get V_max ≈.
In other words — as if you have never seen this before
325 V
2. What do we already know?
Copy these onto the left of your page, one per line, with units: 230 V. Mixing cm with m, or minutes with seconds, loses a method mark.
3. Which method — and why this one?
325 V
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: 230 V. 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: V_max ≈. Circle that word — that is the missing variable.
Find: We are required to find: V_max ≈. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate: What we need to calculate: 325 V. Then substitute the given, one line at a time, to get V_max ≈.
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: 230 V. 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
325 V
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
Vmax=Vrms √2 ≈ 325 V.
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
325 V
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
325 V
Copy onto your answer sheet — in this order
Answer: 325 V
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 · 3 Marks
Source approaching a stationary listener. Observed frequency 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: Source approaching a stationary listener. Observed frequency 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 frequency is. Circle that word — that is the missing variable.
Find
We are required to find: Observed frequency is. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate
What we need to calculate: Approaching. Then substitute the given, one line at a time, to get Observed frequency is.
In other words — as if you have never seen this before
Approaching → higher pitch. Minus in the denominator.
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?
Approaching → higher pitch. Minus in the denominator.
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 frequency is. Circle that word — that is the missing variable.
Find: We are required to find: Observed frequency is. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate: What we need to calculate: Approaching. Then substitute the given, one line at a time, to get Observed frequency 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
Approaching → higher pitch. Minus in the denominator.
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
Approaching → higher pitch. Minus in the denominator.
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
higher than source
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 than source
Copy onto your answer sheet — in this order
Answer: higher than source
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…”
25 · 2 Marks · Work, energy & power
Work to lift 10 kg through 2 m (g = 10)
Formulas
W=F Δx cosθ
Work
P=WΔt=F v
Power
Notes: m = 10 kg. Δh = 2 m. g = 10. Lifted slowly, ΔK = 0.
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: Work to lift 10 kg through 2 m (g = 10)
Before any working — hunt first
Given
Numbers and units already in the sentence: 10 kg · 2 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: Work to lift 10 kg through 2 m (g = 10). Circle that word — that is the missing variable.
Find
We are required to find: Work to lift 10 kg through 2 m (g = 10). Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate
Write W = mgh with empty letters. Cross out every letter that already has a number. Calculate the letter that is still standing — that gives Work to lift 10 kg through 2 m (g = 10).
In other words — as if you have never seen this before
W = ΔEp = mgh when you lift against gravity.
2. What do we already know?
m = 10 kg. Δh = 2 m. g = 10. Lifted slowly, ΔK = 0.
3. Which method — and why this one?
W = ΔEp = mgh when you lift against gravity.
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 kg · 2 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: Work to lift 10 kg through 2 m (g = 10). Circle that word — that is the missing variable.
Find: We are required to find: Work to lift 10 kg through 2 m (g = 10). Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate: Write W = mgh with empty letters. Cross out every letter that already has a number. Calculate the letter that is still standing — that gives Work to lift 10 kg through 2 m (g = 10).
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. Δh = 2 m. g = 10. Lifted slowly, ΔK = 0.
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 = ΔEp = mgh when you lift against gravity.
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
Write mgh
W=10×10×2=200 J.
W=mgh
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
200 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
200 J
Copy onto your answer sheet — in this order
Formula: W=mgh
Answer: 200 J
6. Check it like a marker
A 100 N weight through 2 m is 200 J. Matches.
7. A trap first-timers fall into
W = mgh is not work.
26 · 4 Marks · Work, energy & power
Work by 80 N through 5 m at 60°
Formulas
W=F Δx cosθ
Work
P=WΔt=F v
Power
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: Work by 80 N through 5 m at 60°
Before any working — hunt first
Given
Numbers and units already in the sentence: 80 N · 5 m · 60°. 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: Work by 80 N through 5 m at 60°. Circle that word — that is the missing variable.
Find
We are required to find: Work by 80 N through 5 m at 60°. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate
What we need to calculate: 200 J. Then substitute the given, one line at a time, to get Work by 80 N through 5 m at 60°.
In other words — as if you have never seen this before
200 J
2. What do we already know?
Copy these onto the left of your page, one per line, with units: 80 N · 5 m · 60°. Mixing cm with m, or minutes with seconds, loses a method mark.
3. Which method — and why this one?
200 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: 80 N · 5 m · 60°. 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: Work by 80 N through 5 m at 60°. Circle that word — that is the missing variable.
Find: We are required to find: Work by 80 N through 5 m at 60°. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate: What we need to calculate: 200 J. Then substitute the given, one line at a time, to get Work by 80 N through 5 m at 60°.
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: 80 N · 5 m · 60°. 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
200 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 = F Δx cosθ = 80 × 5 × cos 60° = 400 × 0.5 = 200 J. The cosine picks only the component along the displacement.
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
200 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
200 J
Copy onto your answer sheet — in this order
Answer: 200 J
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 · 2 Marks · Work, energy & power
Force 10 N through 3 m in the same direction. Work?
Formulas
W=F Δx cosθ
Work
P=WΔt=F v
Power
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: Force 10 N through 3 m in the same direction. Work?
Before any working — hunt first
Given
Numbers and units already in the sentence: 10 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: Work. Circle that word — that is the missing variable.
Find
We are required to find: Work. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate
What we need to calculate: W = FΔx cos0 = 30 J. Then substitute the given, one line at a time, to get Work.
In other words — as if you have never seen this before
W=FΔx cos0=30 J.
2. What do we already know?
Copy these onto the left of your page, one per line, with units: 10 N · 3 m. Mixing cm with m, or minutes with seconds, loses a method mark.
3. Which method — and why this one?
W=FΔx cos0=30 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: 10 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: Work. Circle that word — that is the missing variable.
Find: We are required to find: Work. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate: What we need to calculate: W = FΔx cos0 = 30 J. Then substitute the given, one line at a time, to get Work.
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 · 3 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
W=FΔx cos0=30 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=FΔx cos0=30 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
30 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
30 J
Copy onto your answer sheet — in this order
Answer: 30 J
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…”
28 · 4 Marks · Work, energy & power
Lenz’s law says the induced current
Formulas
W=F Δx cosθ
Work
P=WΔt=F v
Power
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: Lenz’s law says the induced current
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: Lenz’s law says the induced current. Circle that word — that is the missing variable.
Find
We are required to find: Lenz’s law says the induced current. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate
What we need to calculate: Conservation of energy — nature fights the change. Then substitute the given, one line at a time, to get Lenz’s law says the induced current.
In other words — as if you have never seen this before
Conservation of energy — nature fights the change.
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?
Conservation of energy — nature fights the change.
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: Lenz’s law says the induced current. Circle that word — that is the missing variable.
Find: We are required to find: Lenz’s law says the induced current. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate: What we need to calculate: Conservation of energy — nature fights the change. Then substitute the given, one line at a time, to get Lenz’s law says the induced current.
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
Conservation of energy — nature fights the change.
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
Conservation of energy — nature fights the change.
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
opposes the change in flux
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
opposes the change in flux
Copy onto your answer sheet — in this order
Answer: opposes the change in flux
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…”
29 · 2 Marks · Momentum & impulse
Momentum of 5 kg at 2 m·s⁻¹
Momentum & impulse
Formulas
p=m v
Momentum
Fnet Δt=Δp
Impulse-momentum theorem
Notes: m=5 kg, v=2 m·s⁻¹. Unknown: p.
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: Momentum of 5 kg at 2 m·s⁻¹
Before any working — hunt first
Given
Numbers and units already in the sentence: 5 kg · 2 m·s⁻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: Momentum of 5 kg at 2 m·s⁻¹. Circle that word — that is the missing variable.
Find
We are required to find: Momentum of 5 kg at 2 m·s⁻¹. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate
Write p = mv with empty letters. Cross out every letter that already has a number. Calculate the letter that is still standing — that gives Momentum of 5 kg at 2 m·s⁻¹.
In other words — as if you have never seen this before
p = mv. A vector; here only magnitude is asked.
2. What do we already know?
m=5 kg, v=2 m·s⁻¹. Unknown: p.
3. Which method — and why this one?
p = mv. A vector; here only magnitude is asked.
4. Step-by-step working
01 / 05
Write p = mv
Momentum is mass times velocity.
p=mv
Why this step: Write the formula before numbers. The memo awards a method mark for the law even if a digit slips later.
02 / 05
Multiply
p=5×2=10 kg·m·s⁻¹.
p=10 kg·m·s⁻¹
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
10 kg·m·s⁻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.
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
10 kg·m·s⁻¹
Copy onto your answer sheet — in this order
Formula: p=mv
Answer: 10 kg·m·s⁻¹
6. Check it like a marker
Units kg·m·s⁻¹. 10 is bigger than 5 and 2, as a product should be.
7. A trap first-timers fall into
Do not divide (2.5) and do not use ½mv² (that is energy, 10 J here by coincidence of numbers).
30 · 4 Marks · Doppler effect
Source moving away from a Durban listener. Observed f is
Doppler effect
Formulas
fL=fs (v ± vL)(v ± vs)
Doppler formula
Notes: Source recedes. Listener at rest. Sound (or any wave) in air.
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: Source moving away from a Durban listener. 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_L = f_s v(v + v_s) 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
Doppler: a receding source stretches the wavelength, so the pitch drops. In the NSC formula the plus sits in the denominator.
2. What do we already know?
Source recedes. Listener at rest. Sound (or any wave) in air.
3. Which method — and why this one?
Doppler: a receding source stretches the wavelength, so the pitch drops. In the NSC formula the plus sits in the denominator.
4. Step-by-step working
01 / 05
Picture the waves
Crests are laid down further apart behind a moving source. Bigger λ, and v = fλ with v fixed, so f drops.
Why this step: Ambulance going away sounds lower. Coming towards you it sounds higher. You already know this from the street.
02 / 05
NSC sign memory
f_L = f_s (v ± vL) / (v ± v_s). Source away: plus in the denominator, which makes f_L smaller.
fL=fs v(v + vs)
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.
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
lower than source f
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
lower than source f
Copy onto your answer sheet — in this order
Formula: fL=fs v(v + vs)
Answer: lower than source f
6. Check it like a marker
Away → lower. Towards → higher. Stationary → equal. Zero would mean no wave at all.
7. A trap first-timers fall into
Mixing the listener and source signs. A moving listener towards the source also raises f, but that plus sits on the numerator.