Question

At what velocity does water emerge from an orifice in a tank in which gauge pressure is

$3\times {10}^{5}N{m}^{-2}$ before the flow starts? (Take the density of water= 1000 kg m${}^{-3}$.)

• A. $24.5m{s}^{-1}$
• B. $14.5m{s}^{-1}$
• C. $34.5m{s}^{-1}$
• D. $44.5m{s}^{-1}$

Answer 1

Answer: (A)

$24.5m{s}^{-1}$

Here,$P=3\times {10}^{5}N{m}^{-2},$

$\rho =1000kg{m}^{-3},$

$g=9.8m{s}^{-2}$
As $P=h\rho g$

$\therefore h=\frac{P}{\rho g}=\frac{3\times {10}^5}{1000\times 9.8}m$

Velocity of efflux,

$v=\sqrt{2gh}=\sqrt{\frac{2\times 9.8\times 3\times {10}^5}{1000\times 9.8}}$

$=\sqrt{600}=24.495m{s}^{-1}=24.5m{s}^{-1}$