A cylinder has inner and outer radii of 4 cm4cm and 8 cm8cm, respectively, and a mass of 3 kg3kg. If the cylinder's frequency of counterclockwise rotation about its center changes from 5 Hz5Hz to 7 Hz7Hz, by how much does its angular momentum change?

1 Answer
Feb 3, 2017

The aswer is =0.15kgms^(-1)=0.15kgms1

Explanation:

The angular momentum is L=IomegaL=Iω

where II is the moment of inertia

and omegaω is the angular velocity

The change of angular momentum is

DeltaL=IDelta omega

For a cylinder, I=m(r_1^2+r_2^2)/2

So, I=3*(0.04^2+0.08^2)/2=0.012kgm^2

Delta omega=(7-5)*2pi rads^-1

DeltaL=0.012*4pi=0.15kgms^(-1)