2.55  standard acceleration due to Earth’s gravity. The value adopted in the International Bureau of Weights and Measures and confirmed in 1913 by the 5th General Conference on Weights and Measures as the standard for acceleration due to gravity. Unit, meter per second-squared. Symbol, gn.

Annotation 1          This “standard value” (gn = 9.80665 m/s2 = 980.665 cm/s2 = 386.089 in/s2 = 32.1740 ft/s2) should be used to determine the ratio of a measurement of the acceleration due to gravity at any location on Earth to the standard acceleration due to gravity.

Annotation 2          Frequently, the magnitude of acceleration is expressed as a multiplier of gn.

Annotation 3          The actual acceleration produced by the force of gravity at or below the surface of the Earth varies with the latitude and elevation of the point of observation. This variable often is expressed using the symbol g. Caution should be exercised when this is done so as not to create an ambiguity with this use and the standard symbol for the unit of the gram as the unit of mass.

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