A solid disk, spinning counter-clockwise, has a mass of #14 kg# and a radius of #3/4 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
Feb 23, 2017

Answer:

The angular momentum is #=25.7kgm^2s^-1#
The angular velocity is #=6.52rads^-1#

Explanation:

The angular velocity is

#omega=v/r#

where,

#v=7/9ms^(-1)#

#r=3/4m#

So,

#omega=(7/9)/(3/4)*2pi=56/27pi=6.52rads^-1#

The angular momentum is #L=Iomega#

where #I# is the moment of inertia

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

So, #I=14*(3/4)^2/2=63/16=63/16kgm^2#

#L=6.52*63/16=25.7kgm^2s^-1#