A boy weighing 500N runs up the stairs to a height of 10 m in 20 seconds. What power the boy develops.

P = 500 N;

h = 10 m;

t = 20 s;

N -?

To calculate the power that the boy develops, we use the formula: N = A / t, where N is the power of the boy, A is the work done by the boy, t is the time during which the work was done.

Since the work is calculated according to the formula A = Ph (P is the boy’s weight, h is the height), then N = Ph / t.

N = (500 N * 10 m) / 20 s = 250 W.

Answer: the boy develops a power equal to 250 watts.