1. The problem statement, all variables and given/known data A man (75kg) is sledding down a 20m high hill that is at an angle of 30 degrees. He is given a push that has him initially going 7m/s. He experiences a force of friction of 22N on his way down the hill. a) How much work is done by friction on his way down the hill? b) How fast is he going when he gets to the bottom? 2. Relevant equations W=Fdcos(Θ), MEi + W = MEf 3. The attempt at a solution For (part a) I thought you had to use 1/2mvi2 + W = mgh but I feel like I am messing something up with the potential and kinetic energy. For (part b) I know you solve for final velocity but I'm not sure if you use 1/2mvi2+ mgh + W = 1/2mvf2 after getting the answer for work.