center of mass

wotz d moment of inertiaof a square plate :
A)alongs itz diameter?
b)axis perpendicular n passing through the center??????

6 Answers

62
Lokesh Verma ·

this can be solved in a very neat way without doing all the 'dirty' calculations!

moment of inertia along AA' = I

by symmetry, along BB' = I

Along CC'=I1 = DD' (Find I1... this i leave for u.. it is easy... if u cant i will do it for u)

So i will give u the solution in terms of I1

Now if I along the perpendicular is Iz

By perpendicular axis theorem, Iz= ICC' + IDD' = 2I1

Also, Iz= IAA' + IBB' = 2I
thus, 2I1=2I

Thus, I1=I

So, i guess u have ur answer? or not yet?!

62
Lokesh Verma ·

oops forgot the image: here it is:

1
skygirl ·

this is actually direct application of perpendicular axes theorem... came in AIEEE this year...... very popular question but easy enuf.

1
mydreamsbig ·

yeah u rite ....
kkk btw d answr for ths years tht aeee ques u tokin bout is 2/3ma(square)....noe??????

1
skygirl ·

i am sorry dear.... i lost this year's paper soon after i came out of the exam hall... bad luck...
i jus remember that there was a sum very similar to this...
if u wanna know the ans, log on to www.fiitjee.com and search for AIEEE 2008 solutions.... they have it there... ok?

1
mydreamsbig ·

kkk.....

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