1. The problem statement, all variables and given/known data The problem and solution are attached, but I don't think the solution is correct. 2. Relevant equations 3. The attempt at a solution The only thing I don't understand is why Joe needs to supply the force to move both people. It seems to me that gravity is providing the force to move John, and Joe is simply applying just enough force to give Brian the same acceleration as Joe. So P = (60)(0.75g) Even if Joe doesn't apply any force at all, Brian could continuously pull down on the rope with F=60g and keep himself from falling. And John would accelerate without Joe applying any force at all. Am I correct? Thank you for reading.