Consider a turntable (similar to a playground merry-go-round), of mass, $m$, and radius, $r$, rotating at a constant angular velocity, $\omega$. Assume the mass is uniformly spread throughout the disk of the turntable.
As the turntable rotates it starts to snow. The snow spreads evenly across the disk of the turntable. When it stops snowing the mass of the snow on the turntable is one-fifth that of the turntable.
Which of the following expressions best describes the angular velocity of the turntable after it stops snowing?