Get premium membership and access revision papers with marking schemes, video lessons and live classes.
(a) Figure 12 shows a lorry towing a trailer using a rope.
The lorry exerts a force N on the trailer and the trailer exerts an equal but opposite force M on the lorry. The frictional force between the trailer and the road is F. Explain how the forces N, M and F enable the trailer to move.

(b) Figure 13 shows a frictionless trolley of mass 2kg moving with uniform velocity towards a wall. At the front of the trolley is a spring whose spring
constant is 25 Nm-1. The trolley comes to rest momentarily after compressing the spring by 3cm and the rebounds from the wall.

(i) Determine:
(I) The force exerted on the wall by the spring.
(II) The maximum acceleration of the as it rebounds from the wall.
(ii) State the reason why the trolley acquires a constant velocity after it rebounds.