Chapter 9 - Rotation of Rigid Bodies - Problems - Exercises - Page 297: 9.39

$I = 0.600~kg~m^2$

$\Delta K = \frac{1}{2}I\omega_2^2 - \frac{1}{2}I\omega_1^2$ $\frac{1}{2}I(\omega_2^2 - \omega_1^2) = -500~J$ $I = \frac{-1000~J}{(\omega_2^2 - \omega_1^2)}$ $I = \frac{-1000~J}{[(520~rev/min)(2\pi~rad/rev)(\frac{1~min}{60~s})]^2 - [(650~rev/min)(2\pi~rad/rev)(\frac{1~min}{60~s})]^2}$ $I = 0.600~kg~m^2$