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Grade 12Mechanics

A disc of mass m and radius R is attached to a rectangular plate of the same mass, breadth R and length 2R as shown in the figure. Find the moment of inertia of this system about the axis XX` passing through the centre of the disc and along the plane.

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Profile image of Yash Kumar
9 Years agoGrade 12
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1 Answer

Profile image of Neeladri
9 Years ago
Bhaiya, I am trying to answer.
We know MI of disc is MR2/4 and MI of 
Rectangle wrt its axis is ML2/12=
M(2R)2/12=
MR2/3.
Now by parallel axis theorem, MI of rectangle wrt our axis is MI wrt its axis +M(2R)2=
13MR2/3.
So our and=sum of MIs of disc and rectangle=MR2/4+13MR2/3 =
55MR2/12.
Hope this helps.