Question

The diagram shows Venturi meter through which water is flowing. The speed of water at $X$ is $2\, cm / \sec$. The speed of water at $Y$ in $cm / s$ (taking $g=1000\, cm / \sec ^{2}$ ) is_____.

Answer 1

The speed of water at sections $X$ and $Y$ should be equal. Applying
Bernoulli's equation,
$P_{1}+\frac{1}{2} \rho v_{1}^{2}=P_{2}+\frac{1}{2} \rho v_{2}^{2}$
$\Rightarrow \frac{1}{2} \rho\left(v_{2}^{2}-v_{1}^{2}\right)=P_{1}-P_{2}=h \rho g$
$v_{2}^{2} =v_{1}^{2}+2 g h$
$v_{2} =\sqrt{(2)^{2}+2 \times 1000 \times 0.51}$
$=32\, cm / s$