Question

20. A solid cylinder of mass 20 kg rotates about its axis with angular speed 100

rad/s. The radius of cylinder is 0.25. What is the kinetic energy associated with

the rotation of the cylinder? What is the magnitude of angular momentum if the

cylinder about its axis?​

Answer 1

Answer:

Mass of the cylinder, m = 20 kg

Angular speed, ω = 100 rad s–1

Radius of the cylinder, r = 0.25 m

The moment of inertia of the solid cylinder:

I = mr2 / 2

= (1/2) × 20 × (0.25)2

= 0.625 kg m2

∴ Kinetic energy = (1/2) I ω2

= (1/2) × 6.25 × (100)2 = 3125 J

∴Angular momentum, L = Iω

= 6.25 × 100

= 62.5 Js