Let mass of the larger triangle =M Side of larger triangle =ℓ Moment of inertia of larger triangle =ma2 Mass of smaller triangle =4M Length of smaller triangle =2ℓ Moment of inertia of removed triangle =4M(2a)2 ∴Ioriginal Iremoved =M4M⋅(a)2(2a)2 Iremoved =16I0 So,I=I0−16I0=1615I0
An equilateral triangle ABC is cut from a thin solid sheet of wood. (See figure) D, E and F are the mid-points of its sides as shown and G is the…
JEE Main 2019 — Physics Mechanics
2019mcqmedium
An equilateral triangle ABC is cut from a thin solid sheet of wood. (See figure) D,E and F are the mid-points of its sides as shown and G is the centre of the triangle. The moment of inertia of the triangle about an axis passing through G and perpendicular to the plane of the triangle is I0. If the smaller triangle DEF is removed from ABC, the moment of inertia of the remaining figure about the same axis is I. Then 
Official previous-year question
Held on 11 Jan 2019 · Verified 6 Jul 2026.
Options
- A
I=1615I0
- B
I=43I0
- C
I=169I0
- D
I=4I0
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