A lorry is driven at a constant speed of 20 m/s on a closed test track. A warning light comes on, and the lorry comes to rest 50 m beyond the point where the driver saw the light. The driver's reaction time was measured three times before the test.
| Measurement | Reaction time in s\mathrm{s}s |
|---|---|
| 1 | 0.30 |
| 2 | 0.35 |
| 3 | 0.40 |
Using the mean reaction time, what is the braking distance of the lorry?
7 m7\ \mathrm{m}7 m
43 m43\ \mathrm{m}43 m
50 m50\ \mathrm{m}50 m
57 m57\ \mathrm{m}57 m
126 exam-style questions on Edexcel GCSE Physics 2.5 Stopping and braking distances, covering 2.5.1 Stopping distance and reaction time, 2.5.2 Factors affecting stopping distance, 2.5.3 Dangers of large decelerations, and 2.5.4 Braking distance and initial speed. Each one has a worked solution and a mark scheme showing where the marks go.