A solid disk, spinning counter-clockwise, has a mass of #16 kg# and a radius of #3/7 m#. If a point on the edge of the disk is moving at #7/5 m/s# in the direction perpendicular to the disk's radius, what is the disk's angular momentum and velocity?

1 Answer
Jan 30, 2018

Answer:

The angular momentum is #=4.81kgm^2s^-1# and the angular velocity is #=3.27rads^-1#

Explanation:

The angular velocity is

#omega=(Deltatheta)/(Deltat)#

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

#omega=v/r#

where,

#v=7/5ms^(-1)#

#r=3/7m#

So,

The angular velocity is

#omega=(7/5)/(3/7)=3.27rads^-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= 16kg#

So, #I=16*(3/7)^2/2=1.47kgm^2#

The angular momentum is

#L=1.47*3.27=4.81kgm^2s^-1#