# Doubt in COM of composite Body

Here’s the Question

I tried solving this using principle of superposition and negative centre of mass

Plz tell is the Method correct.

And is there any other Method to solve this?

the method is correct but the inner circles radius is R/2 (you have taken pi R^2 it will be (pi R^2)/4) so you have to solve it accordingly

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Thanks bro

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Can this be solved by any other Method ?@VasuBro @Anorak @Epicure @VictoryGod

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Bro which method do u want? Afaik Superposition is the best method possible for such cavity problems in any field in physics…

Are u confused with what nitin sir did in this… He has made a error while writing the com…

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Exactly yaar. Unhone kaise equation ko equate kiya. Answer wasn’t matching. I was totally confused.

Did sir correct it later? Sir ek hi figure me Teeno COM likhke idk how kisi equation se equate kr dete hain. I didn’t understand how!
@VasuBro

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Sir ne manipulate ki h equations aur kuch nhi…
Sir ne new cm ko kuch r1 distance pe liya h original body(M) k cm se… Aur removed part(m) k cm ko koi dusri distance r2 se…
Fir finally abt original body k cm pe equation lgayi h m1r1=m2r2… Jha m1=M-m aur m2 =m … Aur r1, r2 respective distances…

Isi ko tum new cm k abt likho equation ko… Same result ayega…
Better to follow urs one… Or in whicever u r comfortable…

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Net Mass moment about CM = 0 vale method se bhi kr skte ho

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Han yhi chahye tha . Aur @Aryav ne v bta diya…
Ab bas ye btado Mass Moment kya hota hai🤐

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Body pe kisi mass m x R ka product… R is distance from com…
Ye tum bina naam k bhi use kr hi rhe honge kbhi na kbhi xd…
Jaise moment of momentum ko angular momentum khte h (r x p)

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Thanks guys😁 @VasuBro @Aryav
Ye method bohot OP hai…
Superposition se kam samay lagega.

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Op vopi kuch nhi…seedha coordinate axis k origin ko new cm pe shift krdo… Yhi bnega m1r1=m2r2… Xd Xd

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ek aur noob dbt bro…

iss kosan ko superposition principle se krenge to dono yellow figures me coordinate axis same jgh rhna chahye nah?

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sir gave the idea to do this by finding the \vec{p} of both rings individually and then finding \vec p_{net}
… what if I find the COM of this composite body? then I can find \vec V_{cm} of the body using w_o and then use this to find \vec {p_{cm}}. is this idea correct?
@VasuBro

Yes, obv
New COM Ki position pe fixed h coordinate axis

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