A base ball player has a nightmare. He is accidentally locked in a railroad boxcar. Fortunately, he has his ball and bat along. To start the car moving, he stands at one end bats the ball towards the other end. The impulse exerted by the ball as it hits the end wall, gives the car a forward motion. Sice the ball always rebounds and rolls along the floor back to him, the player repeats this process over and over. Eventually the car attains a very high speed, and the player is killed as the boxcar collides with another car sitting at rest on the track. Analyze this dream and the physics concepts involved in it.