A solid disk, spinning counter-clockwise, has a mass of #2 kg# and a radius of #7/2 m#. If a point on the edge of the disk is moving at #7/4 m/s# in the direction perpendicular to the disk's radius, what is the disk's angular momentum and velocity?

1 Answer
Feb 14, 2017

Answer:

The angular momentum is #=38.5kgm^2s^(-1)#
The angular velocity is #=3.14rads^-1#

Explanation:

The angular velocity is

#omega=v/r#

where,

#v=7/4ms^(-1)#

#r=7/2m#

So,

#omega=(7/4)/(7/2)*2pi=pi=3.14rads^-1#

The angular momentum is #L=Iomega#

where #I# is the moment of inertia

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

So, #I=2*(7/2)^2/2=49/4kgm^2#

#L=3.14*49/4=38.5kgm^2s^(-1)#