A car travelling at 20 m/s hits a wall and stops in 0.10 s. A passenger in the car has a mass of 60 kg. The passenger stops in the same time as the car.
Use the equations:
acceleration=change in velocitytime\text{acceleration} = \dfrac{\text{change in velocity}}{\text{time}}acceleration=timechange in velocity
force=mass×acceleration\text{force} = \text{mass} \times \text{acceleration}force=mass×acceleration
What is the size of the force needed to stop the passenger?
120 N120\ \text{N}120 N
1200 N1200\ \text{N}1200 N
12 000 N12\,000\ \text{N}12000 N
120 000 N120\,000\ \text{N}120000 N
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.