An elevator is hoisted by its cables at constant speed. Is the total work done on the elevator positive, negative, or zero? Explain.

Solution 2DQ Introduction We have to first figure out the total force acting on the elevator. We can then figure out whether the work done is positive, negative or zero by looking at the direction of force and the displacement. Step 1 The work done on an object is given by W = F · d = Fdcos The elevator is moving at a constant velocity, which means there is no acceleration. So the total force acting on the elevator F = 0. Hence the work done from the above formula is W = 0dcos = 0 So the total work done on the elevator is zero.