Moving frame. In a railroad car traveling at .500 cm/s along a straight track, a head-on collision takes place between a 100-g mass moving with velocity 100 cm/s in the same direction as the train and a .50-g mass moving in the opposite direction at .500 cm/s. Both velocities are relative to the train. After the collision, in the car the ,50-g mass is at rest; what is the velocity of the IOO-g mass? How much kinetic energy has been lost?
Now describe the collision from the point of view of an observer at rest by the track. Is momentum conserved? How much kinetic energy is lost in this frame?