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Moment of Inertia formula

  • Thread starter PSOA
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  • #1
PSOA
icyl2b.gif


Why is the end area of shell [tex]2\pi rdr[/tex]?

Thanks in advance. :rolleyes:
 

Answers and Replies

  • #2
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icyl2b.gif


Why is the end area of shell [tex]2\pi rdr[/tex]?

Thanks in advance. :rolleyes:
It's the area expressed in differential form. To acquire the correct formula, you need to calculate the integral with respect to r.

Intuitively, the differential form means this : to describe an infinitesimal small area, take the circumference 2 times pi times r and make it a bit thicker, expressed by the dr. Integrating over r means that you sum up the area of all this different, very thin, circumferences to get the total circular area.

marlon
 
Last edited:
  • #3
PSOA
Oh, I got that! Thank you marlon! I am giving my first steps over integration. And congratulations for the award!!
 
  • #4
3,763
8
And congratulations for the award!!
What award ?
I just lost my guru badge to somebody else, lol.

marlon
 

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