Question

A cylinder has inner and outer radii of `8 cm` and `16 cm`, respectively, and a mass of `6 kg`. If the cylinder's frequency of counterclockwise rotation about its center changes from `9 Hz` to `7 Hz`, by how much does its angular momentum change?

Answer 1

The answer is `=1.21kgms^(-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=6*((0.08)^2+0.16^2)/2=0.096kgm^2`

`Delta omega=(9-7)*2pi=4pirads^-1`

`DeltaL=0.096*4pi=1.21kgms^(-1)`