# Two asteroids, Asteroid X and Asteroid Y, are orbiting the Sun. Asteroid X orbits closer to the Sun than Asteroid Y. Explain why Asteroid X travels at a greater orbital speed than Asteroid Y.

> Pearson Edexcel International GCSE Physics (4PH1) — 1.4 Astronomy · Explain · 4 marks

> Asteroids are rocky bodies that orbit the Sun. Most asteroids are found in the asteroid belt, located between the orbits of Mars and Jupiter, although some have orbits that bring them closer to the Sun than others.

## Mark scheme (4 marks)

1. Gravity / gravitational force is the non-contact force that keeps the asteroids in orbit (acting towards the Sun)
2. The gravitational force on Asteroid X is greater because it is closer to the Sun
3. The greater gravitational force causes a greater (centripetal) acceleration towards the Sun
4. A greater acceleration towards the Sun requires a higher orbital speed to maintain a stable orbit at that smaller radius

## Key terms

- [orbital speed](https://www.gradenine.co.uk/glossary/orbital-speed)

## Related

- [Revision notes for Pearson Edexcel International GCSE Physics (4PH1)](https://www.gradenine.co.uk/learn)
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Source: [GradeNine](https://www.gradenine.co.uk/q/two-asteroids-asteroid-x-and-asteroid-ed9c98c2) · Published by Druglandscape Ltd.