2. An open cylindrical water tank is 30ft in diameter, and the normal depth of water inside is 25ft. The outlet is a 4-inch horizontal valve at the bottom lateral face of the tank. Neglect losses due to friction. If the valve is suddenly opened, what is the initial exit flow rate and velocity of water from the tank? As the tank is emptied, the water level inside gradually decreases, which also results to a decrease in the exit flow rate in the hole below. Derive a simple equation showing the relationship between exit flow rate and velocity versus time for this example