Fs W = F s W = F s cos 180 o W = - F s Maximum negative work.
mgmg F When the load goes up, gravity does negative work and the crane does positive work. When the load goes down, gravity does positive work and the crane does negative work.
A box is being moved with a velocity v by a force P (parallel to v) along a level floor. The normal force is F N, the frictional force is f k, and the weight of the box is mg. Decide which forces do positive, zero, or negative work.