Question

A cylinder has inner and outer radii of `4 cm` and `18 cm`, respectively, and a mass of `2 kg`. If the cylinder's frequency of counterclockwise rotation about its center changes from `15 Hz` to `16 Hz`, by how much does its angular momentum change?

Answer 1

The change in angular momentum is `=0.214kgm^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=2*(0.04^2+0.18^2)/2=0.034kgm^2`

The change in angular momentum is

`DeltaL=IDelta omega`

The change in angular velocity is

`Delta omega=(16-15)*2pi=2pirads^-1`

The change in angular momentum is

`DeltaL=0.034*2pi=0.214kgm^2s^-1`