# A rock climber descends a cliff face using a rope. As she descends, she moves at a constant velocity. Explain why the climber moves at a constant velocity, referring to the forces acting on her.

> OCR GCSE Physics A: Gateway Science (J249) — P2.3 Forces in action · Explain · 4 marks

> A rock climber of mass 65 kg descends a cliff face at a constant velocity. Friction from the rope and air resistance both act on her as she moves downward.

## Mark scheme (4 marks)

1. Weight acts vertically downwards on the climber
2. Friction from the rope (and/or air resistance) acts upwards, opposing her motion
3. The resultant force is zero / the forces are balanced
4. By Newton's First Law, a zero resultant force means the climber continues at a constant velocity

## Key terms

- [constant velocity](https://www.gradenine.co.uk/glossary/constant-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-rock-climber-descends-a-cliff-a6398cfb) · Published by Druglandscape Ltd.