## College Physics (4th Edition)

The energy that is expended is $53,450~J$
We can find the increase in gravitational potential energy: $mgh = (80.0~kg)(9.80~m/s^2)(15~m) = 11,760~J$ This work is 22% of the total energy expended by the muscles. We can find the total energy that was expended: $0.22~E = 11,760~J$ $E = \frac{11,760~J}{0.22}$ $E = 53,450~J$ The energy that is expended is $53,450~J$.