A solid disk, spinning counter-clockwise, has a mass of #8 kg# and a radius of #5/2 m#. If a point on the edge of the disk is moving at #15/4 m/s# in the direction perpendicular to the disk's radius, what is the disk's angular momentum and velocity?

1 Answer
Feb 26, 2017

Answer:

The angular momentum is #=235.6kgm^2s^-1#
The angular velocity is #=9.42rads^-1#

Explanation:

The angular velocity is

#omega=v/r#

where,

#v=15/4ms^(-1)#

#r=5/2m#

So,

#omega=(15/4)/(5/2)*2pi=3pi=9.42rads^-1#

The angular momentum is #L=Iomega#

where #I# is the moment of inertia

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

So, #I=8*(5/2)^2/2=25kgm^2#

#L=9.42*25=235.6kgm^2s^-1#