(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

A disk is rotating freely at 1,000 revolutions per minute about a vertical axis through its center. A hoop with twice the mass of the disk and the same radius as the uniform disk is poised exactly above and is initially at rest. The hop is dropped gently upon the disk so that their rims coincide. The common angular velocity of the disk-hoop combination is:

2. Relevant equations

Conservation of Angular Momentum:

I1w1 = I2w2

3. The attempt at a solution

I1w1 = I2w2

1/2MR^2 x 1000 rpm = 2MR^2 w2

w2 = 1/2MR^2 x 1000 rpm/ 2MR^2

w2 = 250 rev/min

is this correct?

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# Homework Help: Finding a common angular velocity

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