# A solid disk, spinning counter-clockwise, has a mass of #8 kg# and a radius of #5/2 m#. If a point on the edge of the disk is moving at #5/8 m/s# in the direction perpendicular to the disk's radius, what is the disk's angular momentum and velocity?

##### 1 Answer

#### Explanation:

Because a point on the outside of the disk moves along the circumference with

The angular velocity,

As a side note, you could obtain this immediately if you are familiar with the expression

The angular momentum of the disk is

For a uniform disk,

Therefore,

Done, but if you wanted to solve for the inertia on your own without looking it up, you would have to integrate.

Assume the disk has uniform density

where