A solid disk, spinning counter-clockwise, has a mass of #5 kg# and a radius of #6 m#. If a point on the edge of the disk is moving at #19 m/s# in the direction perpendicular to the disk's radius, what is the disk's angular momentum and velocity?

1 Answer
Jun 10, 2018

Answer:

The angular momentum is #=285.3kgm^2s^-1#. The angular velocity is #=3.17rads^-1#

Explanation:

The angular velocity is

#omega=(Deltatheta)/(Deltat)#

#v=r*((Deltatheta)/(Deltat))=r omega#

#omega=v/r#

where,

#v=19ms^(-1)#

#r=6m#

So,

The angular velocity is

#omega=(19)/(6)=3.17rads^-1#

The angular momentum is #L=Iomega#

where #I# is the moment of inertia

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

The mass is #m= 5kg#

So, the moment of inertia is

#I=5*(6)^2/2=90kgm^2#

The angular momentum is

#L=Iomega=90*3.17=285.3kgm^2s^-1#