## College Physics (4th Edition)

The correct answer is: (b) increasing the volume, keeping $P$ and $N$ constant
We can write an expression for the average kinetic energy: $\overline{KE} = \frac{3}{2}~\frac{PV}{N}$ $\overline{KE} = \frac{3}{2}~kT$ We can see that the average kinetic energy of the gas increases if the volume increases while $P$ and $N$ remain constant. The correct answer is: (b) increasing the volume, keeping $P$ and $N$ constant