# A cyclist rides along a flat road and then brakes to a complete stop. Explain what happens to the kinetic energy of the cyclist and bicycle as they slow down, and explain why the total energy of the cyclist-bicycle system is still conserved.

> Edexcel GCSE Physics (1PH0) — 3.1 Conservation of energy · Explain · 4 marks

> A cyclist travelling at speed applies the brakes and comes to a complete stop on a flat road.

## Mark scheme (4 marks)

1. The kinetic energy of the cyclist and bicycle decreases (as they slow down / as speed decreases).
2. The kinetic energy is transferred to heat (thermal energy) via the brakes / through friction between the brake pads and wheels.
3. This heat energy is dissipated to the surroundings (e.g. the air / road).
4. Energy is conserved because it has been transferred / stored in a different form rather than created or destroyed — the total energy remains constant.

## Key terms

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

## Related

- [Revision notes for Edexcel GCSE Physics (1PH0)](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-cyclist-rides-along-a-flat-ffb683c0) · Published by Druglandscape Ltd.