Question

A unifor4m equilateral triangular lamina of side a has mass m. Its moment of inertia about the axis passing through the centroid and prependicular to the plane of the lamina is :-

A. `(2ma^(2))/(3)`
B. `(ma^(3))/(3)`
C. `(ma^(2))/(6)`
D. `(ma^(2))/(12)`

Answer 1

Correct Answer - A
Any uniform triangular lamina can be represented by three point masses for purpose of calculation of moment of inertia.

Required moment of inertia
`=3xx[(m)/(3)((a)/(2sqrt(3)))^(2)]=(ma^(2))/(12)`