A tank of water has a hose coming out of the top. The hose is filled with water and the other end is below the tank, so that the system acts as a syphon. The end of the hose outside the tank is at height h = 0 meters. The bottom of the tank is at height h1, the end of the hose inside the tank is at height h2, and the top of the water is at height h3. Assume the flow is without viscosity.
Which is the best expression for the pressure at the bottom of the tank?