[SOLVED] Please Check to See if I'm Doing Work-Energy Problem Correctly 1. The problem statement, all variables and given/known data A child riding a bicycle has a total mass of 40 kg. The child approaches the top of a hill that is 10 m high and 100 m long at 5 m/s. If the force of friction between the bicycle and the hill is 20 N, what is the child's velocity at the bottom of the hill? 2. Relevant equations K = 1/2 * mv^2, U = mgh, W = delta E, W = Fx * cos(theta) 3. The attempt at a solution Can someone check to see if I'm doing this correctly. I think what they're trying to say is that you're already at the top. I would first do K-initial + U-initial = 4420 J. Then Then set that to Fx and solve for F which is 44.2 N. Subtract 20 N from that and you get 24.2 N and multiply it back by x which gives you 242 J. Set that to K-final and solve for v and you get 11 m/s. Did I do everything correctly?