posted by dave .
hi, reading over momentum notes and i just want to clarify a few things.
if i had a system containing a cart that was moving (cart 1) and then a cart that was stationary (cart2)would there be any net external force acting on the system between the initial position of cart 1 and the final position of the two carts, after they have collided? if there isn't any net external force acting on the system, then is it fair to say that the momentum before the collision is equal to the momentum after the collision? Also, would the final velocity be greater than the initial velocity?