1. The problem statement, all variables and given/known data Two carts are put back-to back on a track. Cart A has a spring-loaded piston; cart B, which has twice the inertial mass of cart A, is entirely passive. When the piston is released, it pushes against cart B, and the carts move apart. How do the magnitudes of the final momenta p and the kinetic energies K compare? Please tell me if my approach is correct, because I'm not very clear on momentum: Well if the piston is pushing against Cart B, then its momentum would be bigger than Cart A because it has both a greater velocity and a greater mass and momentum= velocity * mass. The kinetic energies- wouldn't the KE of cart A be bigger because it has more PE?