1. The problem statement, all variables and given/known data 2. Relevant equations PE at A = 3mgx WD = Fs KE = 1/2mv^2 3. The attempt at a solution The question I am stuck on is part ii. I worked out from part i that the PE at A is 3mgx, so therefore all this must go towards the KE and the sound, and doing work against friction, etc... I said that the change in energy must equal the work done so -3mgx = μmgd, and the mg must cancel so d = -3x/μ However the mark scheme says d = 3x/μ, without the negative. So have I done something wrong or is this just to do with the direction I have chosen?