Question

A hole is in the bottom of the tank having water. If total pressure at the bottom is $3$ atm $(1 \,atm = 10^{5}\, Nm^{-2})$, then velocity of water flowing from hole is

• A. $\sqrt{400}\,ms^{-1}$
• B. $\sqrt{600}\,ms^{-1}$
• C. $\sqrt{60}\,ms^{-1}$
• D. none of these

Answer 1

Answer: (A)

Total pressure $( P )$ = atmospheric pressure $(P_{0})$ + pressure due to water columnn $p$'
$P=P_{0}+P'$
$\therefore P'=P-P_{0}=3-1=2$ atm
or, $\rho gh =2$ atm or, $h\times 10 \times 10^{3}=2\times 10^{5}$
or, $h=20\,m$
Velocity of water coming from hole is
$v=\sqrt{2gh}=\sqrt{2\times10\times20}$
$=\sqrt{400}\,ms^{-1}$