Question

The unit of moment of inertia of an area is

• A. $M^3$
• B. $M^4$
• C. $Kg/M$
• D. $Kg/M^2$

Answer 1

The correct option is B

$M^4$

1. The moment of inertia of an area is the summation of second moments of all areas in the axis.
2. A geometrical characteristic of an area that indicates how its points are distributed with respect to any axis is the second moment of area, also known as the area moment of inertia.
3. The mathematical expression is $I=\underset{}{\sum (A\times d^2)}$, where $I$ is the moment of inertia and $A$ is the area and $d$ is the distance.
4. So, the unit will be $m^2\times m^2=m^4$, where $m$ is the meter.

Hence, option B is correct.