Engineers compare two passenger restraint systems using identical crash-test dummies. Each dummy has a mass of 75 kg and is moving at 18 m/s before being brought to rest.
| Restraint system | Stopping time in s | Contact area in m2\text{m}^2m2 |
|---|---|---|
| P: seat belt only | 0.090 | 0.015 |
| Q: seat belt and airbag | 0.25 | 0.060 |
Assume that the average resultant force exerted by each restraint system acts over the stated contact area.
Give one feature of the vehicle structure, other than a passenger restraint, that can reduce the risk of injury in a collision.
Calculate the average pressure exerted by restraint system Q on the dummy.
Explain why restraint system Q is expected to reduce the risk of injury more than restraint system P. Use data from the table in your answer.
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.