Question

A forklift lifts 5 boxes from the ground to a height of 2 meters (m). The boxes push down with a force of 1000 newtons (N). How much work was done by the forklift to lift the boxes?

Answer 1

The boxes push downward with a force of 1000 N: this means the total weight of the boxes is 1000 N, and then the forklift must do an equal (and opposite) force in order to lift them.
The 5 boxes are lifted by an altitude of $d=2 m$, so the work done by the forklift is equal to the product between the magnitude of the force done by the forklift times the distance covered by the boxes:
$W=Fd=(1000 N)(2 m)=2000 J$