Terresterial Constants

Acceleration of gravity at sea level = 9.806650 meters per second per second (m/s²) = 32.1740 feet per second per second (ft/s²)

Atmospheric pressure = 14.7 pounds per square inch absolute (PSIA) = 760 millimeters of mercury

absolute (mmHgA) = 760 torr (torr) = 1.01325 bar (bar)

Atmospheric gas concentrations:

• Nitrogen = 78.084 %

• Oxygen = 20.946 %

• Argon = 0.934 %

• Carbon Dioxide (CO2) = 0.033 %

• Neon = 18.18 ppm

• Helium = 5.24 ppm

• Methane (CH₄) = 2 ppm

• Krypton = 1.14 ppm

• Hydrogen = 0.5 ppm

• Nitrous Oxide (N₂O) = 0.5 ppm

• Xenon = 0.087 ppm

Density of dry air at 20 ^oC and 760 torr = 1.204 mg/cm³ = 1.204 kg/m3 = 0.075 lb/ft³ = 0.00235 slugs/ft³

Absolute viscosity of dry air at 20 ^oC and 760 torr = 0.018 centipoise (cp) = 1.8 × 10⁻⁵ Pascal-

seconds (Pa·s)