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?

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Answer 1 · 2017-02-27T12:53:03

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

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#

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#