Question

A cylinder has inner and outer radii of `2 cm` and `16 cm`, respectively, and a mass of `1 kg`. If the cylinder's frequency of counterclockwise rotation about its center changes from `10 Hz` to `15 Hz`, by how much does its angular momentum change?

Answer 1

The answer is `=0.41kgms^(-1)`

Explanation:

The angular momentum is `L=Iomega`

where `I` is the moment of inertia

The change in angular momentum is

`DeltaL=IDelta omega`

`Delta omega` is the change in angular velocity

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

So, `I=1*((0.02)^2+0.16^2)/2=0.013kgm^2`

`Delta omega=(15-10)*2pi=10pirads^-1`

`DeltaL=0.013*10pi=0.41kgms^(-1)`