# A student sets up a simple pendulum and observes it swinging back and forth. Describe the motion of the pendulum bob in terms of its displacement, amplitude, and time period. Include in your answer an explanation of what happens to the time period if the amplitude is made larger.

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

> A simple pendulum consists of a small bob attached to a string. When pulled to one side and released, it swings repeatedly through its equilibrium (undisturbed) position.

## Mark scheme (5 marks)

1. The bob oscillates/moves back and forth about its equilibrium (undisturbed) position
2. Amplitude is the maximum displacement of the bob from its equilibrium (undisturbed) position
3. Time period is the time taken for one complete oscillation / swing
4. Increasing the amplitude does NOT change the time period
5. Correct reasoning: although the bob travels a greater distance with larger amplitude, it also moves faster, so the time period is unchanged

## Key terms

- [amplitude](https://www.gradenine.co.uk/glossary/amplitude)
- [time period](https://www.gradenine.co.uk/glossary/time-period)
- [displacement](https://www.gradenine.co.uk/glossary/displacement)

## 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-student-sets-up-a-simple-8a1872ea) · Published by Druglandscape Ltd.