Free Physical quantities & units questions for AS Level Physics (9702), part of Mechanics & materials. Each question has the answer and the marking points an examiner would look for.
Generate a full Physical Quantities & Units worksheet →All Mechanics & materials questionsWhich row correctly classifies the four quantities?
| vector | scalar | |
|---|---|---|
| A | kinetic energy and weight | momentum and power |
| B | momentum and weight | kinetic energy and power |
| C | weight and power | momentum and kinetic energy |
| D | momentum and power | kinetic energy and weight |
Answer: B
Which estimate is closest to the power of a domestic kettle?
Answer: B
Which statement describes homogeneous equation?
Answer: C
A quantity Q is determined using Q = mLT2. The measurements are m = (0.36 ± 0.01) kg, L = (1.160 ± 0.005) m and T = (2.33 ± 0.02) s.
Determine the SI base units of Q.
Calculate Q and its absolute uncertainty. Give your answer to an appropriate number of significant figures.
Distinguish between systematic and random errors, and state how each can be reduced.
| Part | Answer and marking points | Marks |
|---|---|---|
| (a) | kg m s−2 kg m s−2 B1 | 1 |
| (b) | 0.0769 ± 0.004 Q = 0.0769 C1 percentage uncertainties added, with T doubled C1 4.9% C1 ± 0.004, consistent s.f. A1 | 4 |
| (c) | systematic: readings all too high or too low by the same amount (e.g. zero error), reduced by correcting the instrument; random: scatter about the true value, reduced by repeating and averaging systematic: consistent shift from true value B1 random: scatter about true value B1 correct method for reducing each B1 | 3 |
A student measures the distance d moved by a trolley as (5.20 ± 0.02) m in a time t of (1.60 ± 0.05) s.
Calculate the average speed of the trolley.
Calculate the percentage uncertainty in the average speed.
State the speed with its absolute uncertainty, to an appropriate number of significant figures.
| Part | Answer and marking points | Marks |
|---|---|---|
| (a) | 3.25 m s−1 3.25 m s−1 B1 | 1 |
| (b) | 3.5% sum of percentage uncertainties C1 3.5% A1 | 2 |
| (c) | 3.3 ± 0.1 m s−1 3.3 ± 0.1 m s−1 B1 | 1 |
A student determines g using a simple pendulum: g = 4π2LT2. She measures L = 1.200 ± 0.002 m and T = 1.80 ± 0.02 s.
State the difference between a systematic error and a random error.
Calculate the value of g.
Calculate the percentage uncertainty in g.
State g with its absolute uncertainty to an appropriate number of significant figures.
Explain why timing 20 oscillations reduces the percentage uncertainty in T.
Show that the equation is homogeneous with respect to SI base units.
| Part | Answer and marking points | Marks |
|---|---|---|
| (a) | systematic: same size and sign each reading (e.g. zero error); random: scatter about mean systematic error: readings shifted by the same amount / in the same direction (e.g. zero error) B1 random error: unpredictable scatter of readings about the mean B1 | 2 |
| (b) | 14.6 m s−2 14.6 m s−2 B1 | 1 |
| (c) | 2.4% %uncertainty = 0.167% + 2 × 1.11% C1 2.4% A1 | 2 |
| (d) | 14.6 ± 0.3 m s−2 absolute uncertainty 0.3 C1 g = 14.6 ± 0.3 m s−2 A1 | 2 |
| (e) | same reaction-time uncertainty spread over 20 periods the absolute uncertainty from reaction time stays the same B1 so divided over 20 periods the uncertainty in T is 20 times smaller B1 | 2 |
| (f) | m / s² = m s⁻² both sides LHS: m s−2 B1 RHS: m / s2 = m s−2 (4π2 has no units) B1 | 2 |
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Meet Riyaz →Original Cambridge-style practice questions written for mentorriyaz.in. These are not Cambridge past paper questions, and this site is not affiliated with or endorsed by Cambridge University Press & Assessment. Updated 2026-11-04. Paper generator · mentorriyaz.in