1. The problem statement, all variables and given/known data It asks me to work out the work done by force P and it tells me that the ball m has a CONSTANT speed during its displacement. That diagram is taken from a book which has already solved the excercise without using the concepts of energy and conservative forces. It used a complicated way of integrating to determinate the work of P. So since all the forces are conservative this could be solved easily, couldn't it? 2. Relevant equations 3. The attempt at a solution If the speed is constatnt then the ΔK is 0. And we know that ΔK=W so W=0. And we also know that the potential energy ΔU=-W so ΔU=0. But after that I end up writing the integral of P when I don't want to do that. Thanks!