Question:

A 75.0-kg firefighter climbs a flight of stairs 28.0 m high. How much work does he do?

Source: Giancoli, Douglas C., Physics: Principles with Applications, 7th Edition, 2014.

Quick Answer:

$2.06 \times 10^4 \textrm{ J}$

### Transcript for this Giancoli solution

This is Giancoli Answers with Mr. Dychko. The work done by the firefighter is the force he exerts in order to climb the stairs times the vertical height of the stairs. And you have to assume that they are going at constant speed or exterting the minimum force needed, in which case, the force will be equal to his weight which is*mg*. So we have 75 kilograms times 9.8 newtons per kilogram, to get the weight, times 28 meters— height of the stairs, which is 2.06 times 10 to the 4 joules of work done.