A cylinder has inner and outer radii of 8 cm and 15 cm, respectively, and a mass of 1 kg. If the cylinder's frequency of counterclockwise rotation about its center changes from 15 Hz to 12 Hz, by how much does its angular momentum change?

1 Answer
Jul 4, 2018

The change in angular momentum is =0.27kgm^2s^-1

Explanation:

The angular momentum is L=Iomega

where I is the moment of inertia

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

The mass of the cylinder is m=1 kg

The radii are r_1=0.08m and r_2=0.15m

So, the moment of inertia is

I=1*(0.08^2+0.15^2)/2=0.01445kgm^2

The change in angular velocity is

Deltaomega=2pi(15-12)=6pirads^-1

The change in angular momentum is

DeltaL=IDeltaomega=0.01445*6pi=0.27kgm^2s^-1