The Physics Question Bank

Momentum = Mass × Velocity (p = mv): GCSE Physics Questions with Answers

✏️ Paper first! Work out every question on paper before you open the answer. Write down every step – the equation, the numbers with units, the rearranging and the answer with its unit. In the exam, if your final answer is wrong you can still get marks for correct working, but only if the examiner can see it.

10 Higher-tier AQA GCSE Physics questions on momentum (p = mv) that get harder as you go, each with a full worked solution.

Course: Combined Science + Separate Physics  |  Tier: Higher only  |  Equation sheet: given in the exam

📌 KEY DEFINITIONS – learn them word for word

Momentum = mass × velocity. It is a vector, so direction matters. Unit: kg m/s.

Conservation of momentum: in a closed system, the total momentum before an event (a collision or explosion) is equal to the total momentum after the event.

The equation

momentum = mass × velocity    p = m v

QuantitySymbolUnit
momentumpkilogram metres per second (kg m/s)
massmkilograms (kg)
velocityvmetres per second (m/s)

Rearranged: v = p ÷ m  |  m = p ÷ v  |  In a collision or explosion, total momentum before = total momentum after

Use FIFA for every answer

  • F – Formula: write the equation as it appears on the sheet.
  • I – Insert: put in the numbers (convert to standard units first).
  • F – Fix: rearrange to make the unknown the subject.
  • A – Answer: calculate and always give the unit.

Higher tier only: work through all 10. Most questions need rearranging.


Questions

Q1 A 0.16 kg cricket ball is bowled at 30 m/s. Calculate its momentum.

Show solution

F: p = m v
I: p = 0.16 × 30
F: p is already the subject
A: 4.8 kg m/s

Q2 A 1200 kg car has a momentum of 18 000 kg m/s. Calculate its velocity.

Show solution

F: p = m v
I: 18 000 = 1200 × v
F: v = 18 000 ÷ 1200
A: 15 m/s

Q3 A bowling ball rolls at 8 m/s with a momentum of 56 kg m/s. Calculate its mass.

Show solution

F: p = m v
I: 56 = m × 8
F: m = 56 ÷ 8
A: 7 kg

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Q4 A 45 g golf ball has a momentum of 3.15 kg m/s just after being hit. Calculate its speed.

Show solution

Convert first: 45 g = 0.045 kg
F: p = m v
I: 3.15 = 0.045 × v
F: v = 3.15 ÷ 0.045
A: 70 m/s

Q5 A 1500 kg car has a momentum of 30 000 kg m/s. Calculate its speed in km/h.

Show solution

F: p = m v
I: 30 000 = 1500 × v
F: v = 30 000 ÷ 1500 = 20 m/s
A: 20 × 3600 ÷ 1000 = 72 km/h

Q6 A 1000 kg car moving at 12 m/s crashes into a stationary 1500 kg car. They lock together. Calculate their speed just after the crash.

Show solution

Momentum before: p = 1000 × 12 + 0 = 12 000 kg m/s
F: p = m v (after, combined mass 2500 kg)
I: 12 000 = 2500 × v
F: v = 12 000 ÷ 2500
A: 4.8 m/s

Q7 Two ice skaters stand still, then push apart. The 40 kg skater moves off at 3 m/s. Calculate the velocity of the 60 kg skater.

Show solution

Total momentum before = 0, so the two momenta after are equal and opposite
40 kg skater: p = 40 × 3 = 120 kg m/s
F: p = m v
I: 120 = 60 × v
F: v = 120 ÷ 60
A: 2 m/s in the opposite direction

Q8 A cruise ship with a mass of 1.0 × 108 kg has a momentum of 5.0 × 108 kg m/s. Calculate its speed.

Show solution

F: p = m v
I: 5.0 × 108 = 1.0 × 108 × v
F: v = 5.0 × 108 ÷ 1.0 × 108
A: 5.0 m/s

Q9 A 30 000 kg railway wagon moving at 2.0 m/s hits a stationary wagon and they couple together, moving off at 1.2 m/s. Calculate the mass of the second wagon.

Show solution

Momentum before: 30 000 × 2.0 = 60 000 kg m/s
F: p = m v (after)
I: 60 000 = m × 1.2
F: m = 60 000 ÷ 1.2 = 50 000 kg (both wagons)
A: second wagon = 50 000 − 30 000 = 20 000 kg

Q10 A 58 g tennis ball arrives at a racket at 25 m/s and leaves in the opposite direction at 35 m/s. Calculate the size of its change in momentum, to 2 significant figures.

Show solution

Convert first: 58 g = 0.058 kg; take the new direction as positive: before −25 m/s, after +35 m/s
F: p = m v
I: before = 0.058 × −25 = −1.45; after = 0.058 × 35 = 2.03
F: change = 2.03 − (−1.45) = 3.48 kg m/s
A: 3.5 kg m/s (2 s.f.)
Watch out: a change of direction means you add the speeds, not subtract.

🧮 Practise every equation, on paper or on screen

Equations Workbook (£12): printable practice for all the AQA GCSE Physics equations, with 237 questions, 109 worked examples and full answers. Includes a Core booklet with the Higher-only equations removed.

Every Equation PowerPoint (£8): every equation with worked examples, 102 questions and 15 multi-step problems. Good for revising on screen or teaching from the board.

Next steps: learn the whole topic in Forces in 10 steps · more ramped questions: all 12 Forces equations · mix them up: Which equation? Forces

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