# A bowling ball rolling along a smooth lane strikes a stationary skittle. The skittle flies forwards rapidly whilst the bowling ball slows down but continues to move in the same direction. Explain, using Newton's laws of motion and the concept of momentum, why the bowling ball slows down when it strikes the skittle, and why the skittle moves off faster than the bowling ball after the collision.

> OCR A-Level Physics A (H556) — 3.5 Newton's laws and momentum · Explain · 5 marks

> A bowling ball of large mass rolls along a smooth lane at a steady speed and collides with a single, much lighter stationary skittle. After the collision, the skittle shoots forwards at high speed whilst the bowling ball continues forwards but at a noticeably slower speed.

## Mark scheme (5 marks)

1. Before the collision only the bowling ball has momentum (the skittle is stationary / has zero momentum)
2. Newton's third law: the skittle exerts an equal and opposite force on the bowling ball (as the bowling ball exerts on the skittle)
3. The resultant (backwards/decelerating) force on the bowling ball causes it to decelerate / lose momentum (Newton's second law)
4. Total momentum is conserved (the total momentum after the collision equals the total momentum before)
5. Because the skittle has a much smaller mass than the bowling ball, it must have a much greater velocity to account for the momentum it gains, so it moves off faster than the bowling ball

## Key terms

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

## Related

- [Revision notes for OCR A-Level Physics A (H556)](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-bowling-ball-rolling-along-a-ea21f89a) · Published by Druglandscape Ltd.