Question

A solid disk, spinning counter-clockwise, has a mass of `3 kg` and a radius of `3 m`. If a point on the edge of the disk is moving at `8 m/s` in the direction perpendicular to the disk's radius, what is the disk's angular momentum and velocity?

Answer 1

The disc angular momentum is `36 kg m^2s^(-1)`
And the angular velocity is `(8/3) (rad)/s`

Explanation:

The angular momentum is given by `L=I×omega`
Where `I=`moment of inertia
And `omega=`angular velocity

The moment inertia of a disc is given by `I=(mr^2)/2`
where `m=` mass of the disc
And `r=`radius of the disc

Also we use the formula `v=r.omega`

So `omega=v/r=8/3 rad/s`

`I=3.3^2/2=27/2 kg m^2`

And the angular momentum is `L=27/2.(8/3)=36 kg m^2s^(-1)`