http://img339.imageshack.us/img339/5208/blockcartpulleyyb1.gif [Broken] A cart of mass M1 = 3 kg is attached to a block of mass M2 = 4 kg by a string that passes over a frictionless pulley. The system is initially at rest and the table is frictionless. After the block has fallen a distance h = 0.8 m: a) What is the work Wg done by gravity on the system? b) What is the increase in kinetic energy DK of the cart-plus-block system? c) What is the speed |v| of the cart-plus-weight system? d) What is the work Ws done on the cart (not the block!) by the string? e) What is the tension T in the string? Relevant equations Work Energy Theorem, Kinetic Energy: (1/2)mv^2, Potential Energy The thing that's tripping me up is how to incorporate M1 with the work done by gravity on M2. This question confuses me because of the cart. I know that the work done by gravity for this conservative system is the negative change in potential energy, but what is the potential energy of M1? I'm just having trouble figuring out all these parts. Sorry for being so vague.