# A cyclist is travelling along a straight, flat road at a constant velocity of 12 m/s. The cyclist then brakes uniformly and comes to rest in 6 seconds. Explain what the velocity–time graph for the entire journey described would look like, and describe the motion of the cyclist during each phase.

> Edexcel A-Level Physics (9PH0) — 2.1 Motion · Explain · 5 marks

> A cyclist travels at a constant velocity before applying the brakes and stopping.

## Mark scheme (5 marks)

1. The first section of the graph is a horizontal straight line (at 12 m/s), indicating constant velocity.
2. During the constant velocity phase, acceleration is zero (resultant force is zero).
3. The second section of the graph is a straight line with a negative gradient (sloping downward from 12 m/s to 0 m/s).
4. The straight negative gradient indicates uniform / constant deceleration (deceleration is uniform because the gradient is constant).
5. The graph ends at zero velocity after 6 seconds of braking, showing the cyclist has come to rest / stopped.

## Key terms

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

## 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-is-travelling-along-a-d21e84c1) · Published by Druglandscape Ltd.