question_answer

Moment of inertia of an equilateral triangular lamina ABC, about the axis passing through its centre and perpendicular to its plane is I0 as shown in the figure. A cavithy DEF is cut out from the lamina, where D, E, F are the mid points of the sides. Moment of inertia of the remaining part of lamina about the same axis is -                    [JEE Online 08-04-2017]

A)  \[\frac{15}{16}{{I}_{0}}\]       

B)  \[\frac{3{{I}_{0}}}{4}\]

C)  \[\frac{7}{8}{{I}_{0}}\]                      

D)       \[\frac{31{{I}_{0}}}{32}\]

Correct Answer: A

Solution :

[a]