A boy on a swing is pulled to a position 2.34 m off the ground and released. At the fastest and lowest point of the swing the boy is 0.50 m off the ground and travelling 3 m/s. The percent efficiency of this swing system is: A) 70 % B) 25% C) 50% D) 10%

Answer 1

[(1/2 m v^2) / (m g h)] * 100% ... [v^2 / (2 g h)] * 100%

3^2 / [2 * 9.8 * (2.34 - 0.50)] * 100%