Physics problem nonconserative forces?

starting at the top of an icy track a rider proceeds down the track on a sled. The track drops 104m in elevation from top to bottom. (a) in the absence of nonconservative forces such as friction and air resistance, what would be the speed of the rider at the bottom of the track? ume that the speed of the rider at the beginning of the run is realtively small and can be ignored. (b) the best riders reach the bottom with a speed of 38.8 m/s. how much work is done on an 86.0kg rider and sled by nonconservative forces?