# A solid disk, spinning counter-clockwise, has a mass of #11 kg# and a radius of #4/7 m#. If a point on the edge of the disk is moving at #8/5 m/s# in the direction perpendicular to the disk's radius, what is the disk's angular momentum and velocity?

##### 1 Answer

The angular momentum of the disk is

#### Explanation:

Angular momentum is given by

The moment of inertia of a solid disk is given by

We are given that

#omega=v/r=(8/5m/s)/(4/7m)#

#=>omega=14/5(rad)/s#

This is the angular velocity.

#I=1/2mr^2=1/2(11kg)(4/7m)^2#

#=>I=88/49 kgm^2#

This is the moment of inertia.

We can now calculate the angular momentum:

#vecL=Iomega=(88/49kgm^2)*(14/5(rad)/s)#

#=>vecL=176/35 (kgm^2)/s#

#=>vecL~~5 (kgm^2)/s#