5 of 5 The diagram below shows a portion of an amusement park ride. The 100 kg car starts from rest at the top of a 20.0 m tall hill. The car travels down the hill, around a loop, and then up an 8.0 m hill where it finally crashes into a very large spring, which compresses 4.0 m before the car stops. Assume negligible friction throughout. 4.0 m 20.0 m 8.0 m "CO a. What is the velocity of the car when it reaches point B? (12 pts) b. What is the spring constant? (12 pts)