# A solid disk, spinning counter-clockwise, has a mass of #1 kg# and a radius of #7 m#. If a point on the edge of the disk is moving at #9 m/s# in the direction perpendicular to the disk's radius, what is the disk's angular momentum and velocity?

##### 2 Answers

The angular momentum is

The angular velocity is

#### Explanation:

The angular velocity is

where,

So,

The angular momentum is

where

For a solid disc,

So,

The angular momentum is

Angular momentum:

Angular velocity:

#### Explanation:

In this problem, we are given the mass of the disk, the radius of the disk, and the tangential velocity, therefore, we can write out the given information as (in SI units):

Note that angular momentum is

Also note that angular velocity is

First, we need find the angular velocity by plugging the given values into the formula

Now, since we know the moment of inertia for a solid disk is

Therefore, the angular momentum is