Question 243: Properties of Matter

Question

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

Accepted Answer

$$\begin{aligned}
& 	ext { Change in pressure }=\frac{1}{2} ho \mathrm{v}^2 \
& 4.5 	imes 10^4-2.0 	imes 10^4=\frac{1}{2} 	imes 10^3 	imes \mathrm{v}^2 \
& 2.5 	imes 10^4=\frac{1}{2} 	imes 10^3 	imes \mathrm{v}^2 \
& \mathrm{v}^2=50 \
& \mathrm{v}=\sqrt{50} \
& 	ext { Velocity of water }=\sqrt{\mathrm{V}}=\sqrt{50} \
& =\mathrm{V}=50
\end{aligned}$$

Properties of Matter

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