## Essential University Physics: Volume 1 (3rd Edition)

$P=16MW$
(a) We can find the energy stored as follows: $K=\frac{1}{2}I\omega^2$ We plug in the known values to obtain: $K=\frac{1}{2}(2.2\times 10^5)(12\pi)^2$ $K=1.6\times 10^8J$ (b) We can find the power as: $P=\frac{\Delta KE}{t}$ $P=\frac{\frac{1}{2}I(\omega_2^2-\omega_1^2)}{t}$ $P=\frac{\frac{1}{2}\times 2.2\times 10^5((12\pi)^2-(10\pi)^2)}{3}$ $P=16MW$