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 #15/4 m/s# in the direction perpendicular to the disk's radius, what is the disk's angular momentum and velocity?

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Answer 1 · 2016-11-10T06:15:47

The angular velocity is #=15/14 Hz#
The angular momentum #=105/4 kgm^2s^-1#

The angular velocity #omega=v/r#
#v=# velocity #=15/4 ms^(-1)#
and #r=# radius #=7/2 m#
So #omega=15/4*2/7=15/14 Hz#

The angular momentum is #L=I.omega#
#I=# moment of inertia #=mr^2/2#
#I=2*(7/2)^2=2*49/4=49/2 kgm^2#
#L=49/2*15/14=105/4 kgm^2s^(-1)#