Sponsor Area

Units And Measurement

Question
CBSEENPH11017702

A solid cylinder of mass 20 kg rotates about its axis with angular velocity 100 rad/s. The radius of cylinder is 0-25m. Find the magnitude of angular momentum and kinetic energy associated with cylinder.

Solution

Given,
Mass of cylinder, m = 20 kg

Radius of cylinder, r = 0.25m

Angular velocity of cylinder, ω = 100 rad/s
The moment of inertia of cylinder about its axis is,
      straight I equals 1 half mr squared equals 1 half cross times 20 cross times left parenthesis 0.25 right parenthesis squared
       = 0.625 kg m
Now angular momentum of cylinder is, 
L = I w
   = 0.625 x 100
   = 62.5 Js 
Kinetic energy of cylinder is,
straight K. straight E space equals 1 half 1 straight ϖ squared space

space space space space space space space equals 1 half straight x 0.625 straight x open parentheses 100 close parentheses squared space

space space space space space space space equals 3125 space straight J