A solid cylinder of mass 20 kg rotates about its axis with angular speed (100 rad/s). The radius of 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?

Moment of inertia of cylinder about its axis = 1/2 M${ R }_{ 2 }$

M=mass , R = radius

= 1/2 x 20 x 0.25 x 0.25 kg - ${{m}^{2}}$

= 0.625 kg - ${{m}^{2}}$

Kinetic energy of cylinder about its own axis = I ω =0.625 x 100

= 62.5 kg - ${{m}^{2}}$ / s