A solid disk, spinning counter-clockwise, has a mass of #1 kg# and a radius of #5 m#. If a point on the edge of the disk is moving at #4 m/s# in the direction perpendicular to the disk's radius, what is the disk's angular momentum and velocity?

1 Answer
Dec 26, 2016

Answer:

The angular momentum is #=62.8kgms^(-1)#
The angular velocity is #=(8pi)/5 rad s^(-1)#

Explanation:

The angular velocity is

#omega=v/r#

where,

#v=4ms^(-1)#

#r=5m#

So,

#omega=4/5*2pi=(8pi)/5 rad s^(-1)#

The angular momentum is #L=Iomega#

where #I# is the moment of inertia

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

So, #I=1*5^2/2=25/2=12.5kgm^2#

#L=12.5*8/5pi=20pi=62.8kgms^(-1)#