# A sprinter runs a 100 m race. During the first 4 seconds, the sprinter accelerates from rest to a top speed. For the next 6 seconds, the sprinter runs at this top speed. In the final 2 seconds, the sprinter decelerates and crosses the finish line at a lower speed. Describe the motion of the sprinter during each of the three stages of the race, referring to the sprinter's velocity and acceleration in each stage.

> Edexcel GCSE Physics (1PH0) — 2.1 Motion · Describe · 4 marks

> A sprinter runs a 100 m race. During the first 4 seconds, the sprinter accelerates from rest to a top speed. For the next 6 seconds, the sprinter runs at this top speed. In the final 2 seconds, the sprinter decelerates and crosses the finish line at a lower speed.

## Mark scheme (4 marks)

1. During the first stage, the sprinter's velocity increases (from zero) so the acceleration is positive / greater than zero.
2. During the second stage, the velocity is constant (at top speed) so the acceleration is zero.
3. During the third stage, the velocity decreases so the acceleration is negative (deceleration).
4. Correct use of the relationship that acceleration is the change in velocity divided by time (or equivalent), applied to distinguish the three stages — e.g. only when velocity is changing is there a non-zero acceleration.

## Key terms

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

## Related

- [Revision notes for Edexcel GCSE Physics (1PH0)](https://www.gradenine.co.uk/learn)
- [How to answer "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-sprinter-runs-a-100-m-7a329b19) · Published by Druglandscape Ltd.