# A child on a playground swing moves back and forth in simple harmonic motion. Describe the changes in speed and the direction of the restoring force as the child moves from the maximum displacement on one side to the maximum displacement on the other side.

> Eduqas A-Level Physics — 5.1 Simple harmonic motion · Describe · 5 marks

> A child is given a single push on a playground swing. The swing then moves freely, reaching a maximum displacement on each side before returning towards the centre.

## Mark scheme (5 marks)

1. At maximum displacement the child is momentarily stationary / speed is zero
2. The child accelerates (speeds up) as they move towards the equilibrium / centre position
3. The child reaches maximum speed at the equilibrium / centre position
4. The child then decelerates (slows down) moving from the centre to the opposite maximum displacement
5. The restoring force always acts towards the equilibrium / centre position (opposing the displacement)

## Key terms

- [simple harmonic motion](https://www.gradenine.co.uk/glossary/simple-harmonic-motion)
- [maximum displacement](https://www.gradenine.co.uk/glossary/maximum-displacement)
- [restoring force](https://www.gradenine.co.uk/glossary/restoring-force)

## Related

- [Revision notes for Eduqas A-Level Physics](https://www.gradenine.co.uk/learn)
- [How to answer "Describe" 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-child-on-a-playground-swing-2535919e) · Published by Druglandscape Ltd.