A transport research laboratory investigated how driver fatigue affects thinking distance. A participant drove a car at a constant speed of 24 m s-1 in a high-fidelity simulator. When a red hazard light suddenly illuminated, the driver had to press the brake pedal as quickly as possible.
The distance travelled by the car from the instant the light illuminated to the instant the brakes were applied (the thinking distance) was recorded. The test was repeated five times when the participant was well-rested ('Rested' condition) and five times after the participant had been awake for 18 hours ('Fatigued' condition).
The table below shows the results of the experiment.
| Condition | Trial 1 (m) | Trial 2 (m) | Trial 3 (m) | Trial 4 (m) | Trial 5 (m) | Mean distance (m) |
|---|---|---|---|---|---|---|
| Rested | 15.2 | 14.8 | 16.1 | 15.5 | 14.4 | 15.2 |
| Fatigued | 24.8 | 26.5 | 23.9 | 27.2 | 25.4 | Y |
Calculate the mean thinking distance for the 'Fatigued' condition (Y).
Give your answer to 2 significant figures.
39 exam-style questions on Edexcel GCSE Physics 2.5 Stopping and braking distances. Each one has a worked solution and a mark scheme showing where the marks go.