Question

what is air pressure

Answer 1

The air that composes the atmosphere is made of many different gases. ... When gravity acts on the air, the air exerts a force upon the earth called pressure. The typical pressure at sea level is 1013.25 millibars or 14.7 pounds per square inch. A millibar is a unit that is used to report the theatmospheric pressure.

Answer 2

air has weight and it exerts pressure .and the atmosphere exerts it its weight as pressure on the Earth's surface which is called atmospheric pressure or air pressure