Math, asked by sumitverma0108, 1 year ago

Find the moment of inertia I2 for the solid above the xy-plane bounded by the paraboloid z = x² + y² = 9, assuming the mean density to be constant C. please solve it..it's urgent..

Answers

Answered by kvnmurty
2
Consider a disc of radius r and thickness dz at a height of z above the x-y plane. Its radius r is given by the bounding paraboloid r² = x² + y².  
       So r² = z.

Mass dm of the disc = dm = C* π r² * dz = C π z dz
Total mass = M = Integral z = 0 to Z  dm   = πC Z² / 2

We know that MOI of the thin disc = dm r² / 2 
              = (C π z dz) z / 2  =  (C π/2) z² dz

So MOI = integral from 0 to Z  { Cπ/2  z² dz}
             = Cπ/6 * Z³   , in terms of Z
             = M * Z/3     in terms of mass

Given Z = 9,   So  MOI = πC 9³ /6 = 243 C π /2

kvnmurty: click on red heart thanks above pls
kvnmurty: This is for the solid that is bounded by z =0, z = 9, z = x^2+y^2.. the conical shaped paraboloid solid..
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