Two trucks \(P\) and \(Q\), of masses 18000 kg and 16000 kg respectively, collide while moving towards each other in a straight line. Immediately before the collision, both trucks are travelling at the same speed, \(u \mathrm {~ms} ^ { - 1 }\). Immediately after the collision, \(P\) is moving at half its original speed, its direction of motion having been reversed.
Find, in terms of \(u\), the speed of \(Q\) immediately after the collision.
State, with a reason, whether the direction of \(Q\) 's motion has been reversed.
Find, in terms of \(u\), the magnitude of the impulse exerted by \(P\) on \(Q\) in the collision, stating the units of your answer.
The force exerted by each truck on the other in the impact has magnitude \(108000 u \mathrm {~N}\).
Find the time for which the trucks are in contact.