# A stationary ice skater catches a ball thrown towards her. After catching the ball, the skater and ball move together. Explain what happens to the momentum of the skater and ball during this event.

> AQA GCSE Physics (8463) — 4.5.7 Momentum (Phys only) · Explain · 4 marks

> A stationary ice skater stands on a frictionless ice rink. A ball of mass 0.5 kg is thrown horizontally towards her. She catches the ball and moves backwards.

## Mark scheme (4 marks)

1. Before the event, the skater has zero momentum (because she is stationary)
2. The total momentum before the event equals the total momentum after the event (conservation of momentum)
3. The ball has momentum before the catch / the ball's momentum decreases after being caught
4. The skater gains momentum (in the same direction as the ball was travelling), so the skater moves in the direction the ball was thrown

## Key terms

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

## Related

- [Revision notes for AQA GCSE Physics (8463)](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" 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-stationary-ice-skater-catches-a-777175f6) · Published by Druglandscape Ltd.