A sled and rider with a combined mass of 50kg are at the top of a hill that is 15m above the level ground. The sled is given a push providing an initial kinetic energy at the top of the hill of 1600J. A: choosing a reference level at the bottom of the hill what is the potential energy of the sled and rider at the top of the hill? B: After the push what is the total mechanical energy of the sled and rider at the top of the hill? C: If friction is ignored what will be the kinetic energy of the sled and rider at the bottom of the hill? So far I have this..and I'm not sure if it's right. PE=mgh PE= (50kg)*(9.8m/sec squared)*(15m) = 7350J E=PE+KE 1600J+7350J = 8950J after that I'm not really sure. Any help is greatly appreciated!