A solid disk, spinning counter-clockwise, has a mass of #9 kg# and a radius of #4 m#. If a point on the edge of the disk is moving at #15 m/s# in the direction perpendicular to the disk's radius, what is the disk's angular momentum and velocity?

1 Answer
Jan 14, 2017

Answer:

The angular momentum is #=1696.5kgms^(-1)#
The angular velocity is #=23.6rads^-1#

Explanation:

The angular velocity is

#omega=v/r#

where,

#v=15ms^(-1)#

#r=4m#

So,

#omega=15/4*2pi=15/2pi=23.6rads^-1#

The angular momentum is #L=Iomega#

where #I# is the moment of inertia

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

So, #I=9*(4)^2/2=72kgm^2#

#L=15/2pi*72=1696.5kgms^(-1)#