Question

In loading a truck, a man lifts boxes of 100 N each through a height of 1.5 m.

(a) How much work does he do in lifting one box ?

(b) How much energy is transferred when one box is lifted ?

(c) If the man lifts 4 boxes per minute, at what power is he working ? (g = 10 m $s^{-2}$)

Answer 1

(a) Work done in lifting one box,
W=F$\times$dW
=100$\times$1.5=150 J

(b) 150 J

(c) Work done in lifting 4 box,
W'=W$\times$4W'=150$\times$4=600 J
time, t=1 minute=60 s
Power,
P=$\frac{W^{\prime }}{time}$
P=$\frac{600}{60}$=10 Watt