A solid disk, spinning counter-clockwise, has a mass of #18 kg# and a radius of #4 m#. If a point on the edge of the disk is moving at #7/3 m/s# in the direction perpendicular to the disk's radius, what is the disk's angular momentum and velocity?

1 Answer
Dec 8, 2016

Answer:

The angular momentum is #=527.8 kgm^2s^(-1)#
The angular velocity is #=3.7 rads^(-1)#

Explanation:

The angular velocity is

#omega=v/r#

#v=7/3ms^(-1)#

#r=4m#

#omega=7/3*1/4*2pi=(7pi)/6rads^(-1)#

The angular momentum is #L=Iomega#

Where #I# is the moment of inertia

For a solid disc #I=mr^2/2=18*4^2/2=144 kgm^2#

The angular momsntum is
#L=Iomega=144*7pi/6=168pi kgm^2s^(-1)#