A solid cylinder of mass `20 kg` rotates about its axis with angular speed `100 s^(-1)`. 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

Here, `M = 20 kg, R = 0.5 m, omega = 100 s^(-1)`
Moment of inertia of solid cylinder `= (MR^(2))/(2) = (20 xx (0.25)^(2))/(2) = 0.625 kg m^(2)`
`:. K.E.` of rotation `= (1)/(2)I omega^(2) = (1)/(2) xx 0.625 xx (100)^(2) = 3125 J`
Angular momentum, `L = I omega = 0.625 xx 100 = 62.5 Js`