A cylinder has inner and outer radii of 12 cm12cm and 18 cm18cm, respectively, and a mass of 6 kg6kg. If the cylinder's frequency of rotation about its center changes from 4 Hz4Hz to 9 Hz9Hz, by how much does its angular momentum change?

1 Answer
Feb 8, 2017

The answer is =1.47kgm^2s^(-1)=1.47kgm2s1

Explanation:

The angular momentum is L=IomegaL=Iω

where II is he [moment of inertia

The change in angular momentum is

DeltaL=IDelta omega

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

So, I=6*(0.12^2+0.18^2)/2=0.0468kgm^2

Delta omega=(9-4)*2pi=10pirads^-1

Delta L=0.0468*10pi=1.47kgm^2s^(-1)