Q1: A 41.2-kg skater is standing at rest in front of a wall. By pushing against the wall she propels herself backward with a velocity of -1.87 m/s. Her hands are in contact with the wall for 1.21 s. Ignore friction and wind resistance. Find the average force she exerts on the wall (which has the same magnitude, but opposite direction, as the force that the wall applies to her}. Note that this force has :1 irection. which you should indicate with the sign of your answer. Number I Units lb Q2: Before starting this problem. review Conceptual Example 3. The hail comes straight down at a mass rate of mmt=0.0690 kgfs and an initial velocity of vo= -15.0 m/s. Suppose that the hail described there bounces off the roof ofthe car with a velocity of +116 m/s. Ignoring the weight of the hailstones, calculate the magnitude of the force exerted by the hail on the roof. Compare your answer to that obtained in Example 2 for the rain. and verify that your answer is consistent with the conclusion reached in Conceptual Example 3. Number I Units l 1. Q3: A 2.8-kg cart is rolling along a frictionless, horizontal track towards a 1.4-kg cart that is held initially at rest. The carts are loaded with strong magnets that cause them to attract one another. Thus. the speed of each cart increases. At a certain instant before the carts collide. the first cart's velocity is +5.7 m/s. and the second cart's velocity is -1.5 m/s. (al What is the total momentum of the system of the two carts at this instant? lb} What was the velocity of the rst cart when the second cart was still at rest? (aiNumber I Units l ti (bl Number I Units 1 9 Q4: The lead female character in the movie Diamonds Are Forever is standing at the edge ofan offshore oil rig. As she res a gun, she is driven back over the edge and into the sea. Suppose the mass ofa bullet is 0.047 kg and its velocity is +690 mfs. Her mass {including the gun) is 50 kg. {a} What recoil velocity does she acquire in response to a single shot from a stationary position, assuming that no external force keeps her in place? lb) Under the same assumption, what would be her recoil velocity if, instead, she shoots a blank cart ridge that ejects a mass of 5.0 x 10" kg at a velocity of +690 mfs