Air

A $4-$ft$-$high, $3-$ft diameter cylinderical water tank whose top is open to the atmosphere is initally filled with water. A discharge plug near the bottom of the tank is pulled out and a water just whose diameter is $0\mathrm{.}5-$in streams out. The average velocity of the jet is given by

$V=\sqrt[\phantom{2}]{2gh}$

Where $h$ is the height of the water in the tank measured from the elevation of the center of the hole. Determine how long it will take for the water level to drop from $2-$ft to the bottom.