conservation of momentum

[Twigs]

The problem is a railroad flatcar of weight W can roll without friction along a straight horizontal track. Initially, a man of weight w is standing on the car, which is moving to the right with speed v naut(initial speed). What is the change in velocity of the car if the man runs to the left so that his speed relative to the car is (v relative) just before he jumps off at the left end?

Since momentum is conserved, im using the conservation of momentum equation. However, having trouble understanding how to work the problem out. Any help is appreciated.

[cepheid]

Have you done consv. of momentum problems involving objects that break up into several pieces, each with different masses and velocities? (i.e. explosion problems). The strategy should be the same here, I think.