A 19g ball of clay is shot to the right (in the positive -direction) at 21m/s toward a 38g ball of clay at rest. The two balls of clay collide and stick together. Call this reference frame S. 1. What is the total momentum in frame S? 2. What is the velocity V of a reference frame S' in which the total momentum is zero? 3. After the collision, what is the velocity in frame S' of the resulting 57g ball of clay? Answering this question requires only thought, no calculations. 4. Use your answer to part C and the Galilean transformation of velocity to find the post-collision velocity of the 57g ball of clay in reference frame S.