Question

A pipeline of 5 cm diameter is reduced abruptly to 2.5 cm diameter at a section to enable measurement of the water flowing through it. The loss of head at the contraction is 0.5 m. Given that, in metric units,
$\sqrt{2g}=4.43\text{and}\sqrt{g}=3.132,$
the mean velocity in the reduced section will be

• A. 0.5 m/sec
• B. 1.1075 m/sec
• C. 1.566 m/sec
• D. 4.43 m/sec

Answer 1

The correct option is D 4.43 m/sec

$\text{Head loss,}{h}_L=k\frac{V_2^2}{2g}$

$\text{Assuming,}k=0.5,\text{we get}$

$V_2=\sqrt{\frac{h_L}{k}}\sqrt{2g}$

$\Rightarrow V_2=4.43m/s$