A solid disk, spinning counter-clockwise, has a mass of #3 kg# and a radius of #8/5 m#. If a point on the edge of the disk is moving at #7/4 m/s# in the direction perpendicular to the disk's radius, what is the disk's angular momentum and velocity?

1 Answer
Feb 27, 2017

Answer:

The angular momentum is #=31.6kgm^2s^-1#
The angular velocity is #=6.87rads^-1#

Explanation:

The angular velocity is

#omega=v/r#

where,

#v=7/4ms^(-1)#

#r=8/5m#

So,

#omega=(7/4)/(8/5)*2pi=6.87rads^-1#

The angular momentum is #L=Iomega#

where #I# is the moment of inertia

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

So, #I=3*(7/4)^2/2=147/32kgm^2#

#L=6.87*147/32=31.6kgm^2s^-1#