Velocity changes connect to momentum conservation
Momentum conservation connects the velocities before and after a collision. The forces during the collision redistribute momentum between the objects.
Follow the reasoning
- Choose one positive direction for both objects.
- Calculate total momentum before and after the interaction.
- Use their equality to find an unknown velocity.
Try it in a past paper 3
Open the question, then use its mark scheme to check your work.
Question 14
Identify the velocities after an elastic collision between identical particles.
Question 6
Use light-gate speeds, momentum and kinetic energy to analyse an air-track collision.
Question 2
Find impulse and force, then analyse a head-on elastic puck collision.
A curated collection checked against the question papers and mark schemes; not a complete past-paper catalogue. Links open official OCR PDFs in a new tab.
Put the ideas to work
More practice is on its way
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Specification outcomes (4)
- 3.5.1(b) Define linear momentum, p = mv, and understand its vector nature.
- 3.5.1(c) Relate net force to rate of change of momentum, F = Δp / Δt, and recognise F = ma as a special case.
- 3.5.2(a) State and apply the principle of conservation of momentum.
- 3.5.2(c) Distinguish between perfectly elastic and inelastic collisions.