3. As a roller coaster trolley with a mass of 600 kg coasts down the first hill, it drops a vertical distance of 45.0 m from an initial height of 51.0 m above the ground. If, at the bottom of the hill, its speed is 30.0 m/s: (a) what is the trolley's mechanical energy relative to the top of the hill, and (b) what is the trolley's mechanical energy relative to the ground? Answers 1. 7.63 X 1010 ] 2. 150 m/s 3. (a) 5.13 x 103 J (b) 3.05 X 105 ]