i) Jim rides his skate-board down a ramp which is in the shape of a quarter-circle having a radius of 5.00 m. At the bottom of ramp, Jim is moving at 9.00 m/s. Jim and his skate-board encompass a mass of 65.0 kg. Determine how much work is done by the friction as the skate-board goes down the ramp?
ii) The maximum speed of the child on a swing is around 4.9 m/s. The height of child above the ground is around 0.70 m at the lowest point in his motion. Determine how high above the ground is he at his highest point?