# A skydiver jumps from an aircraft and falls towards the ground. Explain why the skydiver first accelerates, then reaches a terminal velocity.

> Edexcel A-Level Physics (9PH0) — 9.1 Kinetic theory and ideal gases · Explain · 5 marks

> A skydiver jumps from an aircraft at high altitude and falls vertically downward.

## Mark scheme (5 marks)

1. Initially, the only significant force acting on the skydiver is weight (downward) / air resistance is zero or very small at the start
2. There is a resultant force downwards, so the skydiver accelerates (Newton's second law / F = ma implied)
3. As speed increases, air resistance increases
4. The resultant force decreases as air resistance increases, so acceleration decreases
5. Eventually air resistance equals weight, so the forces are balanced / resultant force is zero, and the skydiver moves at constant (terminal) velocity

## Key terms

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

## 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-skydiver-jumps-from-an-aircraft-7207a60d) · Published by Druglandscape Ltd.