Question

A mild flat of width 120 mm and thickness 10 mm is bent into an arc of a circle of radius 10 m by applying a pure moment M. If E is $2\times {10}^{5}N/m{m}^2$, then the magnitude of the pure moment M will be

• A. $2\times {10}^{6}Nmm$
• B. $2\times {10}^{5}Nmm$
• C. $0.2\times {10}^{5}Nmm$
• D. $0.2\times {10}^{4}Nmm$

Answer 1

The correct option is B $2\times {10}^{5}Nmm$

Using Bending Formula, $\frac{M}{I}=\frac{E}{R}=\frac{f}{y}$

$M=\frac{2\times {10}^5\times \left(\frac{120\times {10}^3}{12}\right)}{10,000}$

$=2\times {10}^{5}N-mm$