Question

A boy of mass 40 kg runs up flight of 50 steps each 10 cm high in 5 second. Find i) the work done by the boy ii) the power developed. (g = 9.8m * s ^ - 2)​

Answer 1

Explanation:

Given,mass of the boy, m = 40kg

total height gained,h = 50×10 = 500cm = 5m

time taken to climb,t = 5s

g = 9.8m/s²(g can also be taken as 10m/s² for convenience in solving)

Work done by the boy,

W = mgh = 40×9.8×5=1960 J(if g is taken as 10m/s² ans is 2000 J)

Power developed,P=W/t = 1960/5 = 392 W(if g is 10m/s² ans is 400 W)