Mechanical Properties Of Fluids Question 4

Question 4 - 2024 (27 Jan Shift 2)

The reading of pressure metre attached with a closed pipe is $4.5 \times 10^{4} \mathrm{~N} / \mathrm{m}^{2}$. On opening the valve, water starts flowing and the reading of pressure metre falls to $2.0 \times 10^{4} \mathrm{~N} / \mathrm{m}^{2}$. The velocity of water is found to be $\sqrt{\mathrm{V}} \mathrm{m} / \mathrm{s}$. The value of $\mathrm{V}$ is

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Answer: (50)

Solution:

Change in pressure $=\frac{1}{2} \rho \mathrm{v}^{2}$

$4.5 \times 10^{4}-2.0 \times 10^{4}=\frac{1}{2} \times 10^{3} \times \mathrm{v}^{2}$

$2.5 \times 10^{4}=\frac{1}{2} \times 10^{3} \times \mathrm{v}^{2}$

$\mathrm{v}^{2}=50$

$\mathrm{v}=\sqrt{50}$

Velocity of water $=\sqrt{\mathrm{V}}=\sqrt{50}$

$=\mathrm{V}=50$