Question

Determine the moment of inertia of a rectangular beam section with a width of 300 mm and height of 500 mm about its neutral axis.

• A. $1.25 \times 10^7$ mm\(^4\)
• B. $2.5 \times 10^7$ mm\(^4\)
• C. $3.75 \times 10^7$ mm\(^4\)
• D. $4.5 \times 10^7$ mm\(^4\)

Hint:

The formula for the moment of inertia of a rectangle is $\frac{1}{12} b h^3$ where $b$ is the base and $h$ is the height.

Answer 1

The Correct Option is A

The moment of inertia $I$ for a rectangle about its neutral axis is given by: \[ I = \frac{1}{12} b h^3 \] Substituting the values: \[ I = \frac{1}{12} \times 300 \times (500)^3 = 1.25 \times 10^7 \, \text{mm}^4 \]