Question

A water main $160cm$ dia. contains water at a pressure head of $200m$. Take weight of water to be $1000kg/m^3$. The thickness of the metal shell required for the water main, given that the maximum permissible stress in the metal is $400kg/c{m}^2$, will be

• A. $1cm$
• B. $2cm$
• C. $3cm$
• D. $4cm$

Answer 1

The correct option is D $4cm$

$\frac{pd}{2t}\le 400kg/c{m}^2$
$\Rightarrow \frac{100\times 200\times 100\times 160\times 10}{2\times t}\le 400\times {10}^4$
$\Rightarrow t\ge 0.04m$
So, minimum value of $t=4cm$