3- A ball, m = 4 kg moving with v = 5 m/s collides with another ball, m = 6 kg at rest, V2i = 0. They stick together after the collision. (a) Find their common velocity v2f after the collision. What is the velocity of the center of mass before the collision? (b) How much kinetic energy lost during this collision? Before the collision After the collision m1 mo m1 mo