You can balance a seesaw when the torques are balanced in equilibrium â that is, when the sum of the torques is zero and the torques on one side of the fulcrum are equal and opposite to the torques on the other side. For this activity the force is just the weight of the mass given by w = mg.
Likewise, as elevation increases, there is less overlying atmospheric mass, so that atmospheric pressure decreases with increasing elevation.he boiling point is the temperature at which the vapor pressure is equal to the atmospheric pressure around the water. Because of this, the boiling point of water is lower at lower pressure and higher at higher pressure.
By definition, atmospheric or air pressure is the force per unit of area exerted on the Earthâs surface by the weight of the air above the surface. The force exerted by an air mass is created by the molecules that make it up and their size, motion, and number present in the air. 1  These are important factors because they determine the temperature and density of the air and thus its pressure. The number of air molecules above a surface determines air pressure. As the number of molecules increases, they exert more pressure on a surface and the total atmospheric pressure increases. By contrast, if the number of molecules decreases, so too does the air pressure. Today, air pressure is often measured with a mercury or aneroid barometer. A mercury barometer measures the height of a mercury column in a vertical glass tube.