7.

Three events are observed at a baseball game: I. A baseball is thrown by a pitcher. It starts from rest and is traveling at +v as it flies toward the catcher. Il. A baseball is traveling at +vwhen it enters the catcher's glove and stops. Ill. A baseball is traveling at +v when it hits a wall and bounces away from the wall at -v. The change in the momentum of the baseball has the largest magnitude in which case(s)? O Case Ill only O Cases I and II only O Case I only O Case II only O Cases II and Ill onlyTwo carts are positioned on an air track. Cart A has a mass m and has a spring on the end. Cart B has a mass 2m and is at rest. Cart A moves toward cart B at a speed +v until the two carts have an elastic collision. If kx is the final kinetic energy of cart A and kp is the final kinetic energy of cart B, which one of the following relationships is correct after the collision? O KA KBA rocket is propelled forward as very high speed gases are ejected out of its back. Which one of the following is the best explanation as to why the rocket is propelled forward? O The high speed gases push backward on the rocket as they are ejected and propel it forward. O Because the gases are pushing against the air, the air propels the rocket forward. O The rocket is propelled forward due to the conservation of momentum. O The rocket is propelled forward because both energy and momentum must be conserved. O The rocket is propelled forward due to the conservation of energy