A solid disk, spinning counter-clockwise, has a mass of #4 kg# and a radius of #3/4 m#. If a point on the edge of the disk is moving at #5/9 m/s# in the direction perpendicular to the disk's radius, what is the disk's angular momentum and velocity?

1 Answer
Feb 10, 2017

Answer:

The angular momentum is #=5.24kgms^(-1)#
The angular velocity is #=4.65rads^-1#

Explanation:

The angular velocity is

#omega=v/r#

where,

#v=5/9ms^(-1)#

#r=3/4m#

So,

#omega=(5/9)/(3/4)*2pi=(40/27pi)=4.65rads^-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*(3/4)^2/2=9/8kgm^2#

#L=4.65*9/8=5.24kgms^(-1)#