# A skateboarder wearing a safety helmet collides with a wall and comes to rest. The helmet contains a thick layer of foam padding that compresses during the collision. Explain why wearing the helmet reduces the force experienced by the skateboarder's head during the collision.

> Pearson Edexcel International GCSE Physics (4PH1) — 1.3 Forces, movement, shape and momentum · Explain · 4 marks

> During a skateboarding collision, a skateboarder's head strikes a wall. The skateboarder is wearing a helmet fitted with a thick foam padding layer. The skateboarder's head and helmet have a combined mass of 6 kg and are travelling at 4 m/s just before impact, coming to rest after the collision.

## Mark scheme (4 marks)

1. The skateboarder's head undergoes a change in momentum (from moving to stationary) during the collision
2. The foam padding compresses, increasing the time over which the change in momentum occurs
3. Force equals change in momentum divided by time taken, so a longer time results in a smaller force
4. The force experienced by the skateboarder's head is therefore reduced / the helmet protects the head by reducing the impact force

## Key terms

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

## Related

- [Revision notes for Pearson Edexcel International GCSE Physics (4PH1)](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-skateboarder-wearing-a-safety-helmet-bcadf275) · Published by Druglandscape Ltd.