A railroad car of mass 2.40 x 104 kilogram moving at 3.50 m/s collides and couples with two coupled railroad cars, each of the same mass as the single car and moving in the same direction at 1.20 m/s.
(a) Find the speed of the three coupled cars after the collision?
m/s
(b) Find how much kinetic energy is lost in the collision?
J