1. The problem statement, all variables and given/known data The problem is to give the forces that two carts experience in 4 different situations. A java applet was provided to simulate the situations which is http://physics.bu.edu/ulab/prelabs/prelab_forces_1.html" [Broken], but I will describe them as well, just in case you don't have java or don't want to load the applet. 1) Two carts of equal mass colliding. The first of the carts is in motion toward the second, which is stationary. Upon collision, the first cart stops moving and the second begins moving. 2) Two carts of unequal mass colliding. A cart with a mass of 1 unit is moving toward a stationary cart with a mass of 3 units. Upon collision, they both move in opposite directions with respect to each other. 3) One cart of mass 1 unit is pushing a cart with mass of 3 units. 4) One cart is pulling another cart of equal mass using a rope. 2. Relevant equations I suppose F = ma 3. The attempt at a solution 1) Since they are of equal mass I am assuming equal force felt by both carts upon collision. 2) Since the bigger cart has more mass, it should exert more force, therefore the smaller cart should feel more force. 3) The lighter cart should be feeling more force since the heavier massed cart has a greater force. 4) The forces should be equally felt since both carts are feeling the tension from the rope attached to an equal-massed cart. Thanks for any help you could give me, and I'd like to know the reasoning behind any corrections you have if it's not too much trouble (since I'd like to learn the stuff rather than just get answers).