# A student pushes a heavy crate along a factory floor at a constant velocity. Explain why a constant velocity means the resultant force on the crate must be zero, and state what this tells you about the relationship between the pushing force and the friction force acting on the crate.

> Cambridge International IGCSE Physics (0625) — 1.5 Forces · Explain · 4 marks

## Mark scheme (4 marks)

1. Constant velocity means no change in velocity / no acceleration
2. A zero resultant force is required for zero acceleration / Newton's first law applied
3. The pushing force and friction force are equal in magnitude
4. The pushing force and friction force act in opposite directions

## Key terms

- [resultant force](https://www.gradenine.co.uk/glossary/resultant-force)
- [constant velocity](https://www.gradenine.co.uk/glossary/constant-velocity)
- [friction](https://www.gradenine.co.uk/glossary/friction)

## Related

- [Revision notes for Cambridge International IGCSE Physics (0625)](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/a-student-pushes-a-heavy-crate-bdfa9938) · Published by Druglandscape Ltd.