Angular momentum problem

  • Thread starter neelakash
  • Start date
  • #1
511
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Homework Statement



Two masses M each are connected by a rigid rod of negligible mass having length a.The CM of the system is stationary in a gravity free space and the system rotates about the CM. with angular velocity w.One of the rotating masses strikes a third stationary ball of mass M which sticks to it.What is the angular momentum of the three mass system before and after collision?

Homework Equations



The Attempt at a Solution



For the collision conservation of linear momentum will be applicable.
Mv=2Mv' or,v'=v/2=wa/4. From this w' can be calculated.

Prior collision,L=Iw where I is the MI of the two mass system.

After collision, L'=I'w'

Please check if I am correct.
 

Answers and Replies

  • #2
mukundpa
Homework Helper
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the system will rotate about new center of mass. Check for the position of new center of mass!!
 
  • #3
511
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So,we are to be careful to calculate I for the second time.
Second time, CM will be a/3 rd distance away from the mass 2M.Accordingly,I will change.

But angular velocity would be same as w'.Right?
 
  • #4
511
1
There will be no linear momentum...
angular momentum will be conserved...
CM will change the position...
And if one wants to find w',one has to find I' carefully.
 

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