# A book is placed on a table and remains stationary. A student pushes the book horizontally across the table with a constant force. The book accelerates at first, then moves at a constant velocity, and finally comes to rest after the student stops pushing. Explain the forces acting on the book during each of these three stages of its motion.

> WJEC A-Level Physics (Wales) — 1.2 Forces and Newton's laws · Explain · 5 marks

## Mark scheme (5 marks)

1. During acceleration: the student's pushing force is greater than the friction force, so there is a resultant force in the direction of motion
2. During constant velocity: the pushing force equals the friction force, so there is no resultant force (forces are balanced)
3. After the student stops pushing: friction is the only horizontal force, so there is a resultant force opposing motion, causing the book to decelerate and stop

## Key terms

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

## Related

- [Revision notes for WJEC A-Level Physics (Wales)](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-book-is-placed-on-a-e71ede3c) · Published by Druglandscape Ltd.