A certain man needed 400N of force to pull a load through a distance of 150cm in 8s. Calculatell i) the work done by man ii) the power developed by man

a) 600 J

b) 75 W

Explanation:

Force = 400 N, distance = 150 cm = 1.5 m, time = 8s

a) Work is the product of force acting on an object and distance (or displacement). The S. I unit of work is the joules.

Work = force * distance = 400 * 1.5 = 600 J

b) Power is the amount of energy transferred per unit time. It is the ratio of work to time. The S. I unit of power is watt

Power = work/time = 600 / 8 = 75 W