Question

An isosceles triangular piece is cut from a square plate of side l. The piece is one-fourth of the square and mass of the remaining plate is M. The moment of inertia of the plate about an axis passing through O and perpendicular to its plane is?

• A. $\frac{M{l}^2}{6}$
• B. $\frac{M{l}^2}{12}$
• C. $\frac{M{l}^2}{24}$
• D. $\frac{M{l}^2}{3}$

Answer 1

The correct option is A $\frac{M{l}^2}{6}$

ABC is a symmetric part of square of side $l.$

$M.I$ of a square bar of mass $M$ and side $l$ is $\frac{M}{12}(l^2+l^2)=\frac{2M{l}^2}{12}.$

$\therefore M.I=\frac{M{l}^2}{6}$

Hence, the answer is $\frac{M{l}^2}{6}.$