1. The problem statement, all variables and given/known data A 2.2kg block slides down a planar incline. The incline makes an angle of thirty degrees with the horizontal and the block starts 10 m above ground. The coefficient of friction between the block and the incline is .1. The block reaches the bottom of the incline and then slides up an identical incline on the other side. To what vertical height will the block slide on the second incline? Ans. 7m 2. Relevant equations P.E.= mgh Ff=u mg cos (theta) 3. The attempt at a solution The potential energy is =2.2*9.81*10=215.82 Here's where I'm a little unsure. The work done by Ff is u mg cos(theta) * 20 ( the hypotenuse) *2, because you have to account for it up, right? So 215-74.686=141.34 To account for height I think mgh works so 141.34/(2.2*9.81). I get 6.53, not 7. Did I do this correct?