# A motorcyclist is travelling along a road when a pedestrian steps out ahead. Explain why the stopping distance of the motorcycle increases when the motorcyclist is tired.

> Eduqas A-Level Physics — 4.2 Kinetic theory and gases (A-Level only) · Explain · 5 marks

> Stopping distance is made up of two parts: thinking distance and braking distance. A typical human reaction time is between 0.2 and 0.9 seconds.

## Mark scheme (5 marks)

1. Tiredness increases the driver's reaction time
2. A longer reaction time means the motorcycle travels further before the brakes are applied
3. Thinking distance increases (because the motorcycle is still moving at full speed during the reaction time)
4. Stopping distance is the sum of thinking distance and braking distance
5. So the overall stopping distance is greater (because thinking distance has increased)

## Key terms

- [stopping distance](https://www.gradenine.co.uk/glossary/stopping-distance)

## Related

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Source: [GradeNine](https://www.gradenine.co.uk/q/a-motorcyclist-is-travelling-along-a-52dcd9d4) · Published by Druglandscape Ltd.