Answer
$\Delta U $ = – 184 J
Work Step by Step
In Problem 8a, we saw that the work done by the gravitational force was $W_{g}$ = 184 J. Therefore, since $W_{g}$ = – $\Delta U$, the change in potential energy is $\Delta U$ = – 184 J.
This makes sense because the work done transferred from the potential energy of the snowball to its kinetic energy, so that it was able to fall.
We could’ve also calculated it directly with the equation for $\Delta U$:
$\Delta U$ = mg$\Delta h$ = (1.50 kg)(9.8 m/s²)(–12.5 m) = – 184 J
