## College Physics (4th Edition)

The energy that must be supplied to the centrifuge is $573~J$
We can find the rotational kinetic energy of the centrifuge: $KE_{rot} = \frac{1}{2}I~\omega^2$ $KE_{rot} = \frac{1}{2}(6.5\times 10^{-3}~kg~m^2)~(420~rad/s)^2$ $KE_{rot} = 573~J$ Since the change in rotational kinetic energy is $573~J$, the energy that must be supplied to the centrifuge is $573~J$.