What power does a 40 kg boy develop when climbing stairs in 10 seconds to a height of 5 m?

Given:

m = 40 kilograms – the weight of a boy climbing stairs;

t = 10 seconds – the time it takes for the boy to rise;

h = 5 meters – lifting height;

g = 9.8 Newton / meter – acceleration of gravity.

It is required to determine W (Watt) – what power the boy develops.

Let’s find the force of gravity acting on the boy:

F = m * g = 40 * 9.8 = 392 Newtons.

Then, assuming that the boy rises evenly, he performs work equal to:

A = F * h = 392 * 5 = 1960 Joules.

The power will be equal to:

W = A / t = 1960/10 = 196 watts.

Answer: the boy develops a power equal to 196 watts.