Question

In case of a circular section of diameter d, the section modulus is given by:

• A. $\pi d^3 / 16$
• B. $\pi d^2 / 16$
• C. $\pi d^3 / 32$
• D. $\pi d^3 / 64$

Hint:

For circular sections: - Moment of inertia: $I = \frac{\pi d^4}{64}$. - Section modulus: $Z = \frac{\pi d^3}{32}$, important for analyzing bending stresses.

Answer 1

The Correct Option is C

The section modulus ($Z$) for a circular section is calculated using the formula:
\[Z = \frac{I}{y}\]
where:
$I = \frac{\pi d^4}{64}$: Moment of inertia for a circular section,
$y = \frac{d}{2}$: Distance from the neutral axis to the outermost fiber.
Substitute the values:
\[Z = \frac{\frac{\pi d^4}{64}}{\frac{d}{2}} = \frac{\pi d^3}{32}.\]