At what minimum rate is a 60.0-kg boy converting his internal energy when,in 8.00 s,he runs up a flight of stairs that is 10.0-m high?
A)75.0 W
B)735 W
C)4.80 kW
D)48.0 W

Question

Quizplus · Accepted Answer

The potential energy gained by the boy can be calculated by:

Ep = mgh = (60.0 kg)(9.81 m/s^2)(10.0 m) = 5,886 J

This is the amount of energy converted from the boy's internal energy to potential energy as he climbs the stairs. The rate of energy conversion (power) can be calculated as:

P = Ep/t = 5,886 J / 8.00 s = 735 W

Therefore, the minimum rate at which the boy is converting his internal energy is 735 W, which corresponds to choice B.

At What Minimum Rate Is a 60