# A skydiver jumps from an aircraft and falls vertically downwards. At first, the skydiver accelerates. After some time, the skydiver reaches terminal velocity. Explain why the skydiver's acceleration decreases to zero as they fall, before they open their parachute.

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

> A skydiver jumps from an aircraft at high altitude and falls through the atmosphere before opening their parachute.

## Mark scheme (4 marks)

1. As the skydiver speeds up, air resistance (drag) increases
2. The resultant force decreases as air resistance increases (weight remains constant)
3. A smaller resultant force means a smaller acceleration (reference to Newton's Second Law)
4. At terminal velocity, air resistance equals weight, so the resultant force is zero and acceleration is zero

## Key terms

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

## 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-skydiver-jumps-from-an-aircraft-50b87444) · Published by Druglandscape Ltd.