A solid disk, spinning counter-clockwise, has a mass of #4 kg# and a radius of #3/2 m#. If a point on the edge of the disk is moving at #2/7 m/s# in the direction perpendicular to the disk's radius, what is the disk's angular momentum and velocity?

1 Answer
Mar 20, 2017

Answer:

The angular momentum is #=0.86kgm^2s^-1#
The angular velocity is #=0.19rads^-1#

Explanation:

The angular velocity is

#omega=v/r#

where,

#v=2/7ms^(-1)#

#r=3/2m#

So,

#omega=(2/7)/(3/2)=4/21=0.19rads^-1#

The angular momentum is #L=Iomega#

where #I# is the moment of inertia

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

So, #I=4*(3/2)^2/2=9/2kgm^2#

#L=9/2*4/21=0.86kgm^2s^-1#