On a frictionless, horizontal air table, puck A (with mass0.25 kg) is moving toward puck B (with mass 0.350 kg), that is initially at rest. After the collision, puck A has a velocity of 0.120 m/s to the left, and puck B has velocity 0.620 m/s to the right.
a) What was the speed of puck A before the collision?
b) Compute the change in the total kinetic energy of the system that occurs through the collision.