A 1000 kg flat railroad car is rolling to the right at 4.5 m/s. A 60 kg man, is standing on the right end of the cart watching the track in front of the car. He realizes that in front of him, a crane holds a 500 kg bucket of mud that will be dropped on the car in an effort to squash him. He takes off running toward the back of the car at a speed of 10 m/s relative to the car. How fast is the car moving when he jumps off the back end to the left? One second after he jumps off the car, the 500 kg of mud drops vertically onto the car. What is the final speed of the train car with the mud stuck to it?