Question

A simply supported beam has uniform cross-section, b = 100 mm, d = 200 mm, throughout its length. The beam is subjected to a maximum bending moment of $6\times {10}^7$ N-m. The corresponding bending stress developed in the beam is

• A. $30N/m{m}^2$
• B. $60N/m{m}^2$
• C. $90N/m{m}^2$
• D. $120N/m{m}^2$

Answer 1

The correct option is C $90N/m{m}^2$

$\sigma =\frac{M}{I}\times y=\frac{6\times {10}^7}{100\times \left(\frac{{200}^3}{12}\right)}\times \left(\frac{200}{2}\right)=90N/m{m}^2$