1. ## momentum

Two railway trucks, A and B with masses 7m kg and 3m kg respectively, are travelling towards each other on a smooth horizonatl track.
Both trucks are travelling at 3m/s when they collide.
The trucks couple together in the collision and then move together as a single body
i)find the velocity opf the combined trucks immediately after the collision
ii)find in terms of m the magnitude of the impulse A ON B in the collision

Immediately after the collision the truck experiences a braking force which brings them to rest in 24metres.
ii)fidn the magnitude of the braking force.

2. Originally Posted by helpishere
Two railway trucks, A and B with masses 7m kg and 3m kg respectively, are travelling towards each other on a smooth horizonatl track.
Both trucks are travelling at 3m/s when they collide.
The trucks couple together in the collision and then move together as a single body
i)find the velocity opf the combined trucks immediately after the collision
Conservation of linear momentum!

Before collision momentum is 21m-9m kg.m/s. After collision the momentum is 10m v kg.m/s, so:

30m = 10m v

so v=3 m/s in the same direction as the original motion of the heavier truck

ii)find in terms of m the magnitude of the impulse A ON B in the collision
The impulse on B is equal to its change in momentum

Immediately after the collision the truck experiences a braking force which brings them to rest in 24metres.
ii)fidn the magnitude of the braking force.
You should be able to do this, you know the initial velocity, assume a constant breaking force.

RonL