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 #5/9 m/s# in the direction perpendicular to the disk's radius, what is the disk's angular momentum and velocity?

1 Answer
Nov 16, 2016

Answer:

The angular velocity is #=20/63 Hz#
The angular momentum is #=35/36kgm^2s^(-1)#

Explanation:

The angular velocity is #omega=v/r#

where #v= velocity =(5/9)ms^(-1) #

and #r=radius=7/4 m#

#omega=(5/9)/(7/4)=5/9*4/7=20/63 Hz#

The angular momentum is #L=Iomega#

Where #omega= #angular velocity

and #I=# moment of inertia

For a solid disc, #I=(mr^2)/2#

#I=2*(7/4)^2*(1/2)=49/16 kgm^2#

So, #L=(49/16)*20/63=35/36kgm^2s^(-1)#