Question

A horizontal pipe of non uniform cross section has water flow through it such that the velocity is $2m{s}^{-1}$ at a point where the pressure is $40kPa$. The pressure at a point where the velocity of water flow is $3m{s}^{-1}$ is : ( in $kPa$)

• A. $27$
• B. $60$
• C. $37.5$
• D. $40$

Answer 1

The correct option is C $37.5$

Using the bernoulli's therom,

$P_1+\frac{1}{2}p{V}_1^2=P_2+\frac{1}{2}p{V}_2^2$

$\Rightarrow 40\times {10}^3+\frac{1}{2}\times 500\times 4=P_2+\frac{1}{2}\times 1000\times 9$

$\Rightarrow 40\times {10}^3+2000-45000=P_2$

$\Rightarrow 37.5\times {10}^{3}Pa=P_2$

$\Rightarrow P_2=37.5kPa$