A cylinder has inner and outer radii of 2 cm2cm and 3 cm3cm, respectively, and a mass of 1 kg1kg. If the cylinder's frequency of counterclockwise rotation about its center changes from 10 Hz10Hz to 12 Hz12Hz, by how much does its angular momentum change?

1 Answer
Jun 19, 2017

The change in angular momentum is =0.0082kgm^2s^-1=0.0082kgm2s1

Explanation:

The angular momentum is L=IomegaL=Iω

where II is the moment of inertia

The mass, m=1kgm=1kg

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

So, I=1*((0.02^2+0.03^2))/2=0.00065kgm^2I=1(0.022+0.032)2=0.00065kgm2

The change in angular momentum is

DeltaL=IDelta omega

The change in angular velocity is

Delta omega=(12-10)*2pi=(4pi)rads^-1

The change in angular momentum is

DeltaL=0.00065*4pi=0.0082kgm^2s^-1