# A cyclist travels along a flat road. At first, the cyclist accelerates. Eventually, the cyclist reaches a constant speed called terminal velocity. Explain why the cyclist reaches terminal velocity and why the cyclist's speed no longer increases after this point.

> OCR GCSE Physics A: Gateway Science (J249) — P2.1 Motion · Explain · 4 marks

> A cyclist sets off from rest along a straight, flat road. She pedals with a constant thrust force throughout her journey. Her speed gradually increases before she eventually stops accelerating and travels at a steady speed.

## Mark scheme (4 marks)

1. As the cyclist's speed increases, air resistance (drag/friction) increases
2. The resultant force decreases as the opposing forces increase
3. At terminal velocity, the thrust force equals the drag/friction force, so the forces are balanced
4. Because the resultant force is zero, there is no acceleration, so speed remains constant (Newton's First Law)

## Key terms

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

## Related

- [Revision notes for OCR GCSE Physics A: Gateway Science (J249)](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-travels-along-a-flat-49e987b1) · Published by Druglandscape Ltd.