1. The problem statement, all variables and given/known data 2. Relevant equations E(p)=mgh W = Fs 3. The attempt at a solution The book says the crane does mgh amount of work, while gravity does -mgh. What I dont understand is, for the box to be lifted up, doesn't string tension force have to be bigger than gravity - or else it would remain in place and not accelerate upwards? If so, formula for work is W=Fs, the distance s is same for both forces, but string tension force is bigger, so doesnt crane do more absolute work on the box that gravity?