(a(i))[2]
Calculate the car's acceleration.
(a(ii))[2]
Once the first 14 s have passed, the car's speed keeps rising, but the acceleration becomes smaller. From 70 s to 80 s after the start, the car travels at a steady speed of 55 m/s. On Fig. 1.1, sketch one suitable speed-time graph for the car.
(b)[3]
At a later stage, the driver uses the brakes to come to a halt. He is strapped in with a seat belt and slows down while sitting in the seat. A bag placed beside him on the seat slips forwards, moving across the seat towards the front of the car. Using ideas about the forces acting, explain why the driver slows down but the bag slides forwards.