Answer
$\Delta S=\frac{KE}{T_o}$
Work Step by Step
The newly “unavailable” kinetic energy is the heat term in the entropy calculation. Kinetic energy was transformed into thermal energy, which increases the universe’s entropy. Assume the rock and the environment are at a temperature of $T_o$.
$$\Delta S=\frac{Q}{T}=\frac{KE}{T_o}$$
