# A cyclist travels along a straight, flat road. At first, the cyclist accelerates from rest. After a while, the cyclist reaches a constant (terminal) velocity. Eventually, the cyclist stops pedalling and the bicycle slows down to a stop. Describe and explain the motion of the cyclist during each of these three stages, referring to the forces acting at each stage.

> Eduqas A-Level Physics — 1.1 Basic physics quantities and motion · Describe and explain · 5 marks

## Mark scheme (5 marks)

1. During acceleration, the driving force (from pedalling) is greater than the resistive forces (friction/air resistance), so there is a resultant force in the direction of motion.
2. At constant (terminal) velocity, the driving force equals the resistive forces, so the resultant force is zero.
3. When the cyclist stops pedalling, the driving force becomes zero, so the resistive forces produce a resultant force opposing motion.
4. This resultant resistive force causes the cyclist to decelerate (slow down).
5. Work is done against the resistive forces throughout the journey, transferring kinetic energy to heat/thermal energy (and sound).

## Related

- [Revision notes for Eduqas A-Level Physics](https://www.gradenine.co.uk/learn)
- [How to answer "Describe and explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
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Source: [GradeNine](https://www.gradenine.co.uk/q/a-cyclist-travels-along-a-straight-38a26e9a) · Published by Druglandscape Ltd.