Standard gravity

Standard gravity, or standard acceleration due to free fall, usually denoted by g₀ or gₙ, is the nominal acceleration of body in a vacuum near the surface of the Earth. It is defined to be precisely 9.80665 m/s² or 35.30394 (km/h)/s (~32.174 ft/s² or ~21.937 mph/s). This value was established by the 3rd CGPM (1901, CR 70) and used to define the standard weight of an object as the product of its mass and this nominal acceleration. The acceleration of a body near the surface of the Earth is due to the combined effects of gravity and centrifugal acceleration.