A solid disk, spinning counter-clockwise, has a mass of #4 kg# and a radius of #3 m#. If a point on the edge of the disk is moving at #6/5 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 · 2017-02-22T10:36:13

The angular momentum is #=45.2kgm^2s^-1#
The angular velocity is #=2.51rads^-1#

The angular velocity is

#omega=v/r#

where,

#v=6/5ms^(-1)#

#r=3m#

So,

#omega=(6/5)/(3)*2pi=4pi/5=2.51rads^-1#

The angular momentum is #L=Iomega#

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

So, #I=4*(3)^2/2=18kgm^2#

#L=I* omega=2.51*18=45.2kgm^2s^-1#