Question

The figure shows a uniform isosceles triangular plate of mass $M$ and base $L$. The angle at the apex is ${90}^o$. The apex lies at the origin and the base is parallel to the x-axis. Find the moment of inertia of the plane about the y-axis.

Answer 1

$Mass=m$ and Base$=l$

Angle at the apex is $=90°$

Find MI of theplane about the $y-axis=?$

Let, the axis of rotation pass through hypotenuse, considering rotation about hypotenuse you will see triangle.

Diagonal wise$mI=m{l}^{2/6}$

$\therefore base=m{l}^{2/24}$