2. A railroad car with a mass of 5.0 x105 kg collides with a stationary rail-road car of equal mass. After the collision, the two cars lock together and(10)move off

at 4.0 m/s. a) Before the collision, the first rail-road car was moving at 8.0 m/s. What was its momentum? b) What is the total momentum of the two cars after the collision? c) Find the kinetic energies of the two cars before and after the collision. d) Account for the loss of kinetic energy.