A solid disk, spinning counter-clockwise, has a mass of #7 kg# and a radius of #5/2 m#. If a point on the edge of the disk is moving at #4/3 m/s# in the direction perpendicular to the disk's radius, what is the disk's angular momentum and velocity?

1 Answer
Dec 14, 2016

Answer:

The angular momentum is #=146.6kgms^(-1)#

The angular velocity is #=3.35rads^(-1)#

Explanation:

The angular velocity is #omega=v/r#

#v=4/3ms^(-1)#

#r=5/2m#

#omega=4/3*2/5=8/15Hz=16/15pi rads^(-1)=3.35rads^(-1)#

The angulur momentum is #L=Iomega#

The moment of inertia of a solid disc is #=mr^2/2#

#I=7*(5/2)^2=7*25/4kgm^2#

Therefore,

#L=16/15*pi*175/4 kgm^2s^(-1)=146.6kgms^(-1)#