Question

A cylinder has inner and outer radii of `2 cm` and `4 cm`, respectively, and a mass of `12 kg`. If the cylinder's frequency of counterclockwise rotation about its center changes from `4 Hz` to `1 Hz`, by how much does its angular momentum change?

Answer 1

The change in angular momentum is `=18.14 kgms^-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=12*((0.02^2+0.04^2))/2=0.9624kgm^2`

`DeltaL=0.9624(4-1)*2pi=0.9624*6pi=18.14kgms^(-1)`