A solid disk, spinning counter-clockwise, has a mass of #2 kg# and a radius of #7/4 m#. If a point on the edge of the disk is moving at #7/9 m/s# in the direction perpendicular to the disk's radius, what is the disk's angular momentum and velocity?

1 Answer
Nov 11, 2016

Answer:

The angular momentum is #=49/36 kgm^2s^(-1)#
The angular velocity is #=4/9 Hz#

Explanation:

The angular velocity is #omega=v/r#

Here #v=7/9 ms^(-1)# and #r=7/4 m#

therefore #omega = 7/9*4/7=4/9 Hz#

The angular momentum is #L=I*omega#
Where #I# is the moment of inertia
For a solid disc #I=(mr^2)/2=2*(7/4)^2/2=49/16 kgm^2#

So, the angular momentum is #49/16*4/9=49/36 kgm^2s^(-1)#