One coolie takes 1 minute to raise a suitcase through a height of 2 m but the second coolie takes 30 s to raise the same suitcase to the same height. The powers of two coolies are in the ratio
Power, P =$\frac{Work \, done }{Time \, taken }$ Here work done (= mgh) is same in both cases. $\therefore \, \, \, \, \frac{P_1}{P_2}=\frac{t_2}{t_1}=\frac{30 s}{1 \, min}=\frac{30 s}{60 s}=\frac{1}{2}$.