Key Questions

  • If you are ignoring friction and are moving the crate horizontally, you do NO WORK because you neither fought resistance nor changed the potential energy of the crate.

    If, on the other hand, you lift the crate up 20 meters then you did work according to Work = Force x Distance or W = 567n x 20m = 11340 nm = 11340 Joules. This is because you increased the crate's potential energy from 0 Joules on the floor to PE= mgh = 11340 joules on the shelf.

    Note that weight = mass x accel of grav, or w = mg. Since PE=W=mgh, it is also true that W = wh, where height (h) is the distance you lifted it.