# A student pushes a heavy box along a rough floor at a constant speed. Explain why the student must keep applying a force to maintain the constant speed, and describe what happens to the energy transferred by the student during this process.

> OCR GCSE Physics A: Gateway Science (J249) — P7 Energy · Explain · 4 marks

> A student pushes a heavy box along a rough floor at a constant speed across a warehouse. The student notices they are getting warm and can hear the box sliding along the floor.

## Mark scheme (4 marks)

1. Friction acts between the box and the floor (opposing the motion)
2. The student must do work / apply a force over a distance to overcome friction
3. The useful energy transfer / kinetic energy of the box does not increase (because speed is constant)
4. The energy transferred by the student is dissipated / wasted as heat (and sound), which is a waste energy transfer

## Related

- [Revision notes for OCR GCSE Physics A: Gateway Science (J249)](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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