Question

A rod has radius of 200 mm and length of 20 cm_ A 200 N force compresses along its length. Calculate the stress developed in the rod.

• A. $1.62\times {10}^{3}Pa$
• B. $2\times {10}^{2}Pa$
• C. $1.5\times {10}^{3}Pa$
• D. $1.27Pa$

Answer 1

The correct option is A $1.62\times {10}^{3}Pa$

$\begin{array}{c}\text{Given,}\\ \text{Radius}\left(r\right)=200mm=200\times {10}^{-3}m\\ \text{Length}\left(L\right)=20cm=20\times {10}^{-2}m\\ \text{Force}=200N\end{array}$

$\begin{array}{cc}\text{Now},& \\ \text{stress}& =\frac{F}{\text{Area}}\\ & =\frac{200}{\pi r^2}\\ & =\frac{200}{3.14\times {(200\times {10}^{-3})}^2}\\ \text{Stress}& =1.59\times {10}^{3}Pa\end{array}$

$\approx 1.6\times {10}^{3}Pa$

Hence option A is correct