In the railroad freight yard, an empty freight car of massmrolls along a straight level track at1.0m/s and collides with an initially stationary, fully loaded boxcar of mass4.5m. The two cars couple together upon collision.
(a) What is the speed of the two cars after the collision?
m/s
(b) Suppose instead that the two cars are at rest after the collision. With what speed was the loaded boxcar moving before the collision if the empty one was moving at1.0m/s?
m/s