A woman lifts a box weighing 40N from the floor to a shelf 1.5 m above. (a) find the work done by the force (F) the woman exerts on the box (b) Find the work done on the box by its own weight (w) (c ) Find the net work done on the box.

Explanation

(a) work done by the force F, i.e., `W_f = Fs = (40N) (1.5m) = 60J`
(b) The weight of the box (w) acts ina direction opposite to the direction of motion. Thus,
`W_w = - ws= - (40N)(1.5m) =-60J`
(c ) Net work done on the box, `W_(net) = W_f +W_w =+ 60 J - 60J = 0`