A cart of mass m = 2 kg carrying a spring of spring constant k = 48 N/m and moving at speed v = 3.2 m/s hits a stationary cart of mass M = 10 kg. Assume all motion is along a line. a) What is the speed of the center of mass of this system? A: .5333 m/s b) When the spring is at its maximum compression, with what speed are the carts moving in the lab frame? A: .5333 m/s c) How far will the spring be compressed? This is where I have trouble. I know potential energy of spring = 1/2kx^2, but how do i find initial kinetic energy? The equation i tried was the following: (1/2)*m*(Vi+Vcm) = (1/2)*k*x^2 i also tried (1/2)*m*(Vi) = (1/2)*k*x^2, but neither of these worked. any suggestions?