A solid disk, spinning counter-clockwise, has a mass of 5 kg5kg and a radius of 6 m6m. If a point on the edge of the disk is moving at 19 m/s19ms in the direction perpendicular to the disk's radius, what is the disk's angular momentum and velocity?

1 Answer
Jun 10, 2018

The angular momentum is =285.3kgm^2s^-1=285.3kgm2s1. The angular velocity is =3.17rads^-1=3.17rads1

Explanation:

The angular velocity is

omega=(Deltatheta)/(Deltat)

v=r*((Deltatheta)/(Deltat))=r omega

omega=v/r

where,

v=19ms^(-1)

r=6m

So,

The angular velocity is

omega=(19)/(6)=3.17rads^-1

The angular momentum is L=Iomega

where I is the moment of inertia

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

The mass is m= 5kg

So, the moment of inertia is

I=5*(6)^2/2=90kgm^2

The angular momentum is

L=Iomega=90*3.17=285.3kgm^2s^-1