# A cyclist travels at a constant speed along a flat road, then stops pedalling and gradually slows to rest. State what is meant by the term 'deceleration' and describe how the speed–time graph of the cyclist's journey would differ between the constant-speed phase and the slowing phase.

> Cambridge International IGCSE Physics (0625) — 1.2 Motion · State and Describe · 4 marks

## Mark scheme (4 marks)

1. Deceleration is negative acceleration / the rate of decrease of speed (or velocity)
2. During the constant-speed phase the line is horizontal (gradient is zero)
3. During the slowing phase the line slopes downward (has a negative gradient)
4. The gradient of the slowing section represents the (magnitude of the) deceleration / a steeper negative gradient means greater deceleration

## Key terms

- [deceleration](https://www.gradenine.co.uk/glossary/deceleration)
- [speed–time graph](https://www.gradenine.co.uk/glossary/speed-time-graph)
- [constant speed](https://www.gradenine.co.uk/glossary/constant-speed)

## Related

- [Revision notes for Cambridge International IGCSE Physics (0625)](https://www.gradenine.co.uk/learn)
- [How to answer "State and Describe" 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-travels-at-a-constant-86d052e8) · Published by Druglandscape Ltd.