A solid disk, spinning counter-clockwise, has a mass of 8 kg and a radius of 5/2 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?

1 Answer
Feb 26, 2017

The angular momentum is =235.6kgm^2s^-1
The angular velocity is =9.42rads^-1

Explanation:

The angular velocity is

omega=v/r

where,

v=15/4ms^(-1)

r=5/2m

So,

omega=(15/4)/(5/2)*2pi=3pi=9.42rads^-1

The angular momentum is L=Iomega

where I is the moment of inertia

For a solid disc, I=(mr^2)/2

So, I=8*(5/2)^2/2=25kgm^2

L=9.42*25=235.6kgm^2s^-1