## College Physics (4th Edition)

The work done by the wall is $-4170~J$
The work done by the wall on the skater is equal to the skater's change in kinetic energy. We can find the work done by the wall: $Work = KE_2-KE_1$ $Work = 0-\frac{1}{2}mv^2$ $Work = -\frac{1}{2}(69.0~kg)(11.0~m/s)^2$ $Work = -4170~J$ The work done by the wall is $-4170~J$