$7\mathrm{.}37$ In this system $d=25cm,D=40cm,$ and the head loss from the venturi meter to the end of the pipe is given by $h_L=0\mathrm{.}9\frac{V^2}{2}g,$ where $V$ is the velocity in the pipe. Neglecting all other head losses, determine what head $H$ will first initiate cavitation if the atmospheric pressure is $100$kPa absolute$.$ What will be the discharge at incipient cavitation? Assume $=1\mathrm{.}0$ at all locations.