1. The problem statement, all variables and given/known data A person does 115 J of work in throwing a 0.325 kg rock straight up into the air. How high will the rock get, assuming there is 20 J of air resistance? 2. Relevant equations From what I formulated: W = ΔPE The answer says E1 = E2, but I think that's the exact same as the formula I used. 3. The attempt at a solution W = ΔPE 115= mgh - 0 115 = (0.325)(9.8)h - 20 h = 42.386 It looked right in my head, but the problem is that the answer differ in the placement of the -20 J. This is the correct answer given to me: 115 - 20 = Ep2 95 = mgh 95 = (0.325)(9.8)h h = 29.83 30 J (Significant figured) I don't understand why the -20 J should be placed with the work being done (the left side of the equation). I appreciate any attempt at helping me understand the reason.