I have a question about the conservation of momentum and energy in collision problems. What type of situations (elastic/inelastic) can you use the equations to solve for either masses or velocities?? Am I correct?:: Elastic collision: You can use both conservation of momentum + mech. energy to solve for the variables because everything is conserved. Inelastic collision: You can use only conservation of momentum because some energy is wasted as heat or wasted from friction. Can someone give me a better explaination or correct me if I'm wrong? Thanks!