A solid disk, spinning counter-clockwise, has a mass of #7 kg# and a radius of #8 m#. If a point on the edge of the disk is moving at #14 m/s# in the direction perpendicular to the disk's radius, what is the disk's angular momentum and velocity?

1 Answer
Dec 1, 2016

Answer:

The angular velocity is #=1.75 Hz#
The angular momentum is #=686 kgms^(-1)#

Explanation:

The angular velocity is #omega= v/ r #

velocity #=v=14ms^(-1)#

radius #=r=8 m#

#omega=v/r=14/8=7/4 Hz#

The angular momentum is #L=Iomega#

#I=# moment of inertia

For a solid disc, #I=mr^2#

#I=7*8^2=392 kgm^2#

So, the angular momentum is

#L=392*7/4=686 kgms^(-1)#