Question

The pressure of water in a water pipe when tap is opened and closed is respectively $3\times 10^{5}N/m^{2}$ and $3.5\times 10^{5}N/m^{2}$ .With open tap the velocity of water flowing is:

• A. $10m/s$
• B. $5m/s$
• C. $20m/s$
• D. $15m/s$

Answer 1

Answer: (A)

$P_{1}+\frac{1}{2}ρv_{1}^{2}=P_{2}+\frac{1}{2}ρv_{2}^{2}\left(P_{1} - P_{2}\right)=\frac{1}{2}ρv_{2}^{2}$
Since tap is closed, v₁ $=0$
$\left(3 . 5 \times \left(10\right)^{5} - 3 \times \left(10\right)^{5}\right)=\frac{1}{2}\times \left(10\right)^{3}\times v^{2}$
$v=10m/s$