Two loudspeakers are separated by 3 m and are both playing a 686 Hz tone in phase. When you are 5.62 m directly in front of one of the speakers do you hear a minimum or a maximum sound intensity?

Awater-filled u-tube manometer is used to measure the pressure inside a tank that contains air. the water level in the u-tube on the side that connects to the tank is 5 ft above the base of the tank. the water level in the other side of the u-tube (which is open to the atmosphere) is 2 ft above the base. determine the pressure within the tank.