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

Mass `M=20kg`
Angular veloicty `omega=100 "rad"s^(-1)`
Radius `R=0.25m`
Moment of inertia of the cylinder
`I=1/2MR^(2)`
`=1/2xx20xx(0.25)^(2)`
`=0.625kg m^(2)`
(i) Rotational kinetic energy of the cylinder
`=1/2 I omega^(2)`
`=1/2xx0.625xx(100)^(2)`
`=3125J`
(ii) Angular momentum of the cylinder
`L=I omega`
`=0.625xx100`
`=62.5kgm^(2)s^(-1)`