Question

A solid disk, spinning counter-clockwise, has a mass of `12 kg` and a radius of `6 m`. If a point on the edge of the disk is moving at `15 m/s` in the direction perpendicular to the disk's radius, what is the disk's angular momentum and velocity?

Answer 1

The angular momentum is `=720pi=2262kgm^2s^(-1)`
The angular velocity is `=(10pi)/3 =10.5rads^(-1)`

Explanation:

The angular velocity,

`omega=v/r=15/6Hz=5/3*2pirads^(-1)=(10pi)/3 rads^(-1)`

The angular momentum is

`L=Iomega`

Where `I` is the moment of inertia

For a solid disc, `I=1/2*m*r^2`

`I=1/2*12*6^2=216 kgm^2`

The angular momentum is

`L=216*(10pi)/3=(720pi)kg m^2s^(-1)`