Question

A cylinder has inner and outer radii of `9 cm` and `16 cm`, respectively, and a mass of `4 kg`. If the cylinder's frequency of counterclockwise rotation about its center changes from `19 Hz` to `18 Hz`, by how much does its angular momentum change?

Answer 1

THe change in angular momentum is `=0.42kgm^2s^-1`

Explanation:

The angular momentum is `L=Iomega`

where `I` is the moment of inertia

Mass, `m=4kg`

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

So, `I=4*((0.09^2+0.16^2))/2=0.0674kgm^2`

The change in angular momentum is

`DeltaL=IDelta omega`

The change in angular velocity is

`Delta omega=(19-18)*2pi=(2pi)rads^-1`

The change in angular momentum is

`DeltaL=0.0674*2pi=0.42kgm^2s^-1`