Q1. Suppose we had a rubber ball like the ones used for racquetball and put it inside a container with liquid nitrogen. If we let the ball come into thermal equilibrium with the liquid nitrogen, some liquid would begin to appear inside the ball! Why do you think this would happen? (These balls are hollow, a fact that has everything to do with the explanation. What is air made up of?)
Q2. A 100-kg halfback running north with a speed of 12 m/s is tackled by a 110-kg opponent running south with a speed of 4.0 m/s. If collision is completely inelastic and head-on, compute the speed of the players just after the tackle.