A railroad car of mass 2.50 104 kg, is moving with aspeed of 4.09 m/s. Itcollides and couples with three other coupled railroad cars, eachof the same mass as the single car and moving in the same directionwith an initial speed of 2.05 m/s.
(a) What is the speed of the four cars after the collision?
(b) How much energy is transformed into internal energy in the collision?