A solid disk, spinning counter-clockwise, has a mass of #4 kg# and a radius of #7 m#. If a point on the edge of the disk is moving at #8 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 · 2016-10-30T11:03:14

The angular momentum is #=112 kgm^2/s#
The angular velocity is #=8/7 Hz#

Let's start by calculating the angular velocity
we use the equation
#v=8 m/s#
#r=7m#

#v=r*omega#
and #omega=v/r=8/7 Hz#

The moment of inertia of the solid disc #I=m*r^2/2#
So #I=4*7*7/2=98 kgm^2#
Then the angular momentum is #L=Iomega#
so, #L=98*8/7=112kgm^2/s#