1. A person is standing on a completely frictionless surface. Can they walk on this surface? Explain! What could they do to move across the surface? Explain! 2. Suppose there are three astronauts outside their spaceship and that two of them decide to play catch with the third. This means the first two astronauts are attempting to throw the third back and forth. All astronauts weigh the same on earth and are equally strong. The first throws the second and the game begins. Describe the motion of the astronauts as the game proceeds. How long will the game last (i.e. how many throws) ? 3. When a tennis ball is thrown against a wall it appears to bounce back with exactly the same speed as it struck the wall. is momentum conserved for this collision? explain