Two uniform solid cylinders each rotating about its central(longitudinal) axis, have the same mass of 4.92 kg and rotate with the same angular speed of 118rad/s, but they differ in radius .(a) what is the rotational kinetic energy of the smaller cylinder,of radius 0.116? (b) what is the rotational kinetic energy of the larger cylinder of radius 0.691m? (c)now imagine that the smaller cylinder uniformly expands(due to thermal expansion for example) to a new radius of 0.121 m. What is its angular velocity after the expansion?
(hint:what quantity is conserved ).