1. The problem statement, all variables and given/known data A wheel, of radius 200mm, rolls over the top of a hill with a speed of 20m/s and negligible friction losses. (I = 1/2mr^2) 2. Relevant equations Find the speed of the wheel when it is 10m below the top. 3. The attempt at a solution mgh = 1/2mv^2 + 1/2IW^2 W= v/r mgh = 1/2mv^2 + 1/2(1/2mr^2)(v/r)^2 mgh = 1/2mv^2 + 1/4mv^2 gh = 3/4mv^2 v^2 = 4gh/3 v^2 = 4(9.81)(10)/3 v = 11.4m/s I got v = 11.4 m/s but my answer is incorrect as it is different from the answer given which is 23m/s. I want to know the correct solution. I've also tried searching for the height first. h = (3/4v^2)/g h = 30.58m and then 10m below from the top h = 20.58m v^2 = 4gh/3 v^2 = 4(9.81)(20.58)/3 v = 16.41m/s Which is still far from the answer also.