Two water reservoirs A and B are connected to each

other through a 40-m-long, 2-cm-diameter cast iron pipe with

a sharp-edged entrance. The pipe also involves a swing check

valve and a fully open gate valve. The water level in both

reservoirs is the same, but reservoir A is pressurized by compressed air while reservoir B is open to the atmosphere at

88 kPa. If the initial flow rate through the pipe is 1.2 L/s,

determine the absolute air pressure on top of reservoir A.

Take the water temperature to be 10°C