# Explain how a student could estimate the speed of a car travelling along a road, without using any electronic equipment. Give a reasonable value for the speed of a car on a typical UK road.

> AQA A-Level Physics (7408) — 3.1.3 Estimation of Physical Quantities · Explain · 5 marks

## Mark scheme (5 marks)

1. Measure or estimate a known distance along the road (e.g. between two lamp posts or road markings)
2. Time how long the car takes to travel that distance (e.g. using a stopwatch or counting seconds)
3. Use speed = distance ÷ time to calculate the speed
4. Acknowledge a source of uncertainty or suggest a way to improve reliability (e.g. reaction time affects timing; repeat measurements; use a longer distance to reduce percentage error)
5. Give a reasonable value for car speed on a typical UK road in the range 10–35 m/s (or equivalently 30–70 mph / approximately 50 km/h for a standard road)

## Key terms

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

## Related

- [Revision notes for AQA A-Level Physics (7408)](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-a-student-could-estimate-45734d85) · Published by Druglandscape Ltd.