A car is travelling at 14 m/s when it crashes into a wall.
A passenger of mass 70 kg is wearing a seat belt. The passenger comes to rest in 0.20 s.
Use the equation: acceleration=change in velocitytime\text{acceleration} = \dfrac{\text{change in velocity}}{\text{time}}acceleration=timechange in velocity
Calculate the deceleration of the passenger.
Use the equation: force=mass×acceleration\text{force} = \text{mass} \times \text{acceleration}force=mass×acceleration
Calculate the force on the passenger.
In the same crash, a passenger who is not wearing a seat belt hits the dashboard and comes to rest in 0.020 s.
Explain why this passenger is much more likely to be seriously injured.
Name one other safety feature in a car that reduces the force on the passengers in a crash.
50 exam-style questions on OCR GCSE Physics 8.1 Physics on the move, covering 8.1.1 Typical everyday speeds, 8.1.2 Typical everyday accelerations, 8.1.3 Ratios, units and rates on the road, 8.1.4 Human reaction times, 8.1.5 Factors affecting stopping distance, 8.1.6 Stopping distances at different speeds, 8.1.7 Dangers of large decelerations, 8.1.8 Estimating forces in road situations, and 8.1.9 Estimating the effects of large accelerations. Each one has a worked solution and a mark scheme showing where the marks go.