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

We need to find Kinetic energy of the rotating cylinder

We know that, Rotational kinetic energy,

KE = 1/2I ω2

Where

I is moment of inertia

ω is angular velocity

Given

Mass of cylinder, M = 20 kg

Radius of cylinder, R = .25 m = 1/4 m

Angular speed of cylinder, ω = 100 rad s-1

Moment of inertia of a solid cylinder, I = 1/2 MR2

I.e. I = 1/2 × 20 × (1/4)2

= 5/8 kg m2

KE = 1/2 I ω2

= 5/16 (100)2

= 3125 J

= 3.125 kJ

We need to find angular momentum of rotating cylinder about its axis.

Angular momentum, L = I ω

We know that,

Moment of inertia of cylinder, I = 5/8 kg m2

Angular speed of cylinder, ω =100 rad s-1

Angular momentum, L = 5/8 × 100

= 62.5 kg m s-1

= 62.5 J s

Rate this question :

How useful is this solution?
We strive to provide quality solutions. Please rate us to serve you better.
Related Videos
Moment of Inertia | Some special cases40 mins
Interactive Quiz on Moment of Inertia56 mins
Important Questions on Torque43 mins
Centre of Mass Frame (C-Frame)59 mins
Angular momentum & its conservation | Getting Exam Ready37 mins
Understand Parallel & Perpendicular Axis Theorem in detail40 mins
Questions based on rotational motion44 mins
Motion of centre of mass {Theory}38 mins
Interactive Quiz on Torque and angular momentum48 mins
Kinematics of rotational motion about a fixed axis48 mins
Try our Mini CourseMaster Important Topics in 7 DaysLearn from IITians, NITians, Doctors & Academic Experts
Dedicated counsellor for each student
24X7 Doubt Resolution
Daily Report Card
Detailed Performance Evaluation
view all courses