# A cyclist rides along a flat road and then applies the brakes to come to a stop. Explain what happens to the kinetic energy of the cyclist and bicycle during braking, and explain one method the cyclist could use before the journey to reduce the amount of energy wasted when cycling at a constant speed.

> Edexcel A-Level Physics (9PH0) — 3.1 Charge and current · Explain · 5 marks

> A cyclist and their bicycle have a combined mass of 80 kg and are travelling at 10 m/s before the brakes are applied.

## Mark scheme (5 marks)

1. The cyclist and bicycle have kinetic energy because they are moving
2. When the brakes are applied, a friction force acts between the brake pads and the wheel
3. The kinetic energy is transferred to heat / thermal energy (in the brakes and surroundings)
4. The cyclist could lubricate the moving parts (e.g. chain / wheel bearings) of the bicycle
5. Lubrication reduces friction between moving parts, so less energy is wasted as heat during cycling

## Key terms

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

## Related

- [Revision notes for Edexcel A-Level Physics (9PH0)](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-2cae7ba1) · Published by Druglandscape Ltd.