A cylinder has inner and outer radii of 2 cm and 16 cm, respectively, and a mass of 9 kg. If the cylinder's frequency of counterclockwise rotation about its center changes from 10 Hz to 15 Hz, by how much does its angular momentum change?

1 Answer
Feb 27, 2017

The change in angular momentum is =3.68kgm^2s^-1

Explanation:

The angular momentum is L=Iomega

where I is the moment of inertia

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

So, I=9*(0.02^2+0.16^2)/2=0.117kgm^2

The change in angular momentum is

DeltaL=IDelta omega

Delta omega=(15-10)*2pi=10pirads^-1

DeltaL=0.117*10pi=3.68kgm^2s^-1