# Angularr speed of disk

1. Jun 1, 2010

### ghostbuster25

A large flat disk with moment of inertia I is spinning with angular speed 18 rad/s
a small object lands on the disk and changes the moment of inertia to 1.5I

what is the new speed?

i used L=I$$\omega$$ to give me 18*1.5=27 rad/s

i used this because L is the angular momentum of the disk and has a relationship with the angular speed.

Is this correct?

2. Jun 1, 2010

### pgardn

Do you have an equation showing the conservation of angular momentum ie the angular momentum before and after the object lands on the disk? If the moment of Inertia of the item with angular momentum increases, should the angular speed also increase? dont think so...

Last edited: Jun 1, 2010
3. Jun 19, 2010

### inky

Re: angular speed of disk