A solid cylinder of mass 20 kg rotates about its axis with angular speed 100 rad/s. The radius of the cylinder is 0.25 m. What is the kinetic energy associated with the rotation of the cylinder ? What is the magnitude of angular momentum of the cylinder about its axis ?

Explanation

Moment of inertia of cylinder about its axis
`= (1)/(2) MR^(2)`
M = mass, R = radius
`= (1)/(2) xx 20 xx (0.25)^(2) kgm^(2) = 0.625 kg m^(2)`
Kinetic energy of rotating cylinder
`=(1)/(2) I omega^(2) = (1)/(2) (0.625) (100)^(2)J = 3125 J`
Angular momentum of cylinder about its own axis.
`= I omega^(2) = 0.625 xx 100 = 6.25 kg//m^(2)`