railroad car moving at a speed of 3.42 m/s overtakes, collides, and couples with two coupled railroad cars moving in the same direction at 1.11 m/s. all cars have a mass of mass 1.20 105 kg. determine the following. (a) speed of the three coupled cars after the collision (give your answer to at least two decimal places.) m/s (b) kinetic energy lost in the collision