# A tennis ball is travelling towards a wall at 8 m/s. It bounces off the wall and travels back in the opposite direction at 8 m/s. State what happens to the speed, the velocity, and the momentum of the tennis ball as a result of the collision with the wall. Justify your answer for momentum.

> Cambridge International IGCSE Physics (0625) — 1.6 Momentum · State · 4 marks

## Mark scheme (4 marks)

1. The speed remains unchanged / stays the same (at 8 m/s)
2. The velocity changes / is different (because direction has reversed / changed)
3. The momentum changes / is different after the collision
4. Momentum changes because momentum is a vector quantity, so a change in direction means a change in momentum / momentum depends on velocity (which has changed)

## Key terms

- [speed](https://www.gradenine.co.uk/glossary/speed)
- [velocity](https://www.gradenine.co.uk/glossary/velocity)
- [momentum](https://www.gradenine.co.uk/glossary/momentum)

## Related

- [Revision notes for Cambridge International IGCSE Physics (0625)](https://www.gradenine.co.uk/learn)
- [How to answer "State" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

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Source: [GradeNine](https://www.gradenine.co.uk/q/a-tennis-ball-is-travelling-towards-9b2d6bf1) · Published by Druglandscape Ltd.