# Describe how the gravitational force acting on a planet determines its orbital motion around the Sun, and explain why planets closer to the Sun orbit faster than planets further away.

> AQA GCSE Physics (8463) — 4.8.1 Solar system; stability of orbital motions; satellites (Phys only) · Describe and Explain · 4 marks

## Mark scheme (4 marks)

1. Gravity provides the centripetal force that keeps the planet in its orbit
2. The gravitational force is directed towards the Sun / acts inward, causing the planet to travel in a curved/circular path
3. Planets closer to the Sun experience a stronger gravitational force
4. A greater gravitational force means a greater centripetal acceleration / the planet must travel faster to maintain a stable orbit at that smaller radius

## Key terms

- [gravitational force](https://www.gradenine.co.uk/glossary/gravitational-force)
- [orbital motion](https://www.gradenine.co.uk/glossary/orbital-motion)

## Related

- [Revision notes for AQA GCSE Physics (8463)](https://www.gradenine.co.uk/learn)
- [How to answer "Describe and 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/describe-how-the-gravitational-force-acting-8618b71d) · Published by Druglandscape Ltd.