A cylinder has inner and outer radii of 2 cm2cm and 5 cm5cm, respectively, and a mass of 12 kg12kg. If the cylinder's frequency of counterclockwise rotation about its center changes from 6 Hz6Hz to 4 Hz4Hz, by how much does its angular momentum change?

1 Answer
Jun 30, 2017

The change in angular momentum is =0.22kgm^2s^-1=0.22kgm2s1

Explanation:

The angular momentum is L=IomegaL=Iω

where II is the moment of inertia

The mass, m=12kgm=12kg

For a cylinder, I=m((r_1^2+r_2^2))/2I=m(r21+r22)2

So, I=12*((0.02^2+0.05^2))/2=0.0174kgm^2I=12(0.022+0.052)2=0.0174kgm2

The change in angular momentum is

DeltaL=IDelta omega

The change in angular velocity is

Delta omega=(6-4)*2pi=(4pi)rads^-1

The change in angular momentum is

DeltaL=0.0174*4pi=0.22kgm^2s^-1