A uniform disk of mass 21 kg, thickness 0.5 m, and radius 0.6 m is located at the origin, oriented with its axis along the y axis. It rotates clockwise around its axis when viewed from above (that is, you stand at a point on the y axis and look toward the origin at the disk). The disk makes one complete rotation every 0.8 s. What is the rotational angular momentum of the disk

Explanation:

So suppose the axis of rotation is perpendicular to the surface of the disk, then the moment of inertia can be calculated as the following:

We can convert the rotation speed in term of 0.8 seconds per revolution to the angular velocity knowing that each revolution is 2π

Then the rotational angular momentum of the disk is:

In case the axis of rotation is parallel with the surface, the moment of inertia would have a formula of:

f=ma newton

f=100x2.5=250n