A solid disk, spinning counter-clockwise, has a mass of #7 kg# and a radius of #2 m#. If a point on the edge of the disk is moving at #6/7 m/s# in the direction perpendicular to the disk's radius, what is the disk's angular momentum and velocity?

1 Answer
Jan 7, 2017

Answer:

The angular momentum is #=37.7kgm^2s^-1#
The angular velocity is #=2.69rads^-1#

Explanation:

The angular velocity is

#omega=v/r#

where,

#v=6/7ms^(-1)#

#r=2m#

So,

#omega=6/7*1/2*2pi=6/7pi=2.69rads^-1#

The angular momentum is #L=Iomega#

where #I# is the moment of inertia

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

So, #I=7*(2)^2/2=14kgm^2#

#L=6/7pi*14=37.7kgm^2s^(-1)#