# Conservation of Momentum Flat cars

1. Dec 3, 2013

### JamesClarke

1. The problem statement, all variables and given/known data
There are 4 railway flat cars each of mass M travelling with speed v. They're not attached but move together initially without friction. A man of mass m starts at the end and jumps onto the second car, then to the third, and then on to the fourth.When he lands on the 4th it comes to rest. ie imagine the cars moving right and he jumps against motion from the right to the left. Determine the final velocities of the other cars. The man jumps the same speed every time and take the horizontal component of his jump to be u . This u is with respect to the car he jumps from. In the question it says its the same every time. Apparently the result will not depend on u. It says "Assume that the man jumps in the same way with the same velocity each time. You can call u the horizontal component of the velocity of the man wrt to the car he jumps from. The result will not depend on u"

2. Relevant equations
Conservation of momentum i think

3. The attempt at a solution

Pretty stuck any help would be appreciated Do we take the whole system together and then each car seperately? No idea
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

2. Dec 3, 2013

### haruspex

Just try to write the equations for the first jump. How much momentum is added to the car he jumps from?