NEET Questions Solved


The moment of inertia of a cube of mass m and side a about one of its edges is equal to (a) ~ ma 4 3 3

 

 

                                         

First let us find M.I. about axis IC passing through center of cube.
For a square sheet, M.I. about center axis is Ma26 where M is mass of sheet.

                                                  

A cube can be assumed to be made up of infinite square sheets.
 For cube, moment of inertia about center =ma26

Let us try now to find moment of inertia about edge Ix
        Using parallel-axis theorem,

       Ix=Ic+Md2   =ma26+ma22     where d=a2   =23ma2

Difficulty Level:

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  • 17%
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