# Explain how the velocity and kinetic energy of an object undergoing simple harmonic motion (SHM) vary as the object moves from its equilibrium position to a position of maximum displacement.

> IB DP Physics Standard Level (2023 syllabus) — C.1 Simple harmonic motion · Explain · 4 marks

> An object oscillates in simple harmonic motion about a fixed equilibrium position.

## Mark scheme (4 marks)

1. At the equilibrium position the velocity is at its maximum value.
2. As displacement increases towards maximum displacement, the restoring force does negative work on the object, so velocity decreases to zero at maximum displacement.
3. Kinetic energy is proportional to the square of velocity (Ek = ½mv²), so kinetic energy is also maximum at equilibrium.
4. Kinetic energy decreases to zero at maximum displacement as kinetic energy is transferred to potential energy, with the total mechanical energy remaining constant.

## Key terms

- [simple harmonic motion](https://www.gradenine.co.uk/glossary/simple-harmonic-motion)
- [equilibrium position](https://www.gradenine.co.uk/glossary/equilibrium-position)
- [maximum displacement](https://www.gradenine.co.uk/glossary/maximum-displacement)
- [kinetic energy](https://www.gradenine.co.uk/glossary/kinetic-energy)

## Related

- [Revision notes for IB DP Physics Standard Level (2023 syllabus)](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/explain-how-the-velocity-and-kinetic-eeea8ebc) · Published by Druglandscape Ltd.