Velocity graphs reveal momentum changes
For constant mass, momentum follows velocity. The gradient of a velocity–time graph therefore reveals the rate of change of momentum and the resultant force.
Follow the reasoning
- Assign signs to velocities before and after the interval.
- Find the change in momentum, retaining the signs.
- Divide by the interval to find average resultant force.
Try it in a past paper 5
Open the question, then use its mark scheme to check your work.
Question 16
Use a bouncing ball’s velocity–time graph to find the largest momentum-change rate.
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.
Question 24
Calculate the force on a rebounding ball and check its horizontal range.
Show 1 more paper references
Question 3(a)–(d)
Resolve projectile velocity and connect its motion with energy and momentum.
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
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Specification outcomes (4)
- 3.1.1(a) Define and use displacement, instantaneous speed, average speed, velocity and acceleration.
- 3.1.1(d) Use velocity–time graphs to determine acceleration as the gradient and displacement as the area under the graph, including estimation for non-linear graphs.
- 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.