Resolution 2 of the 3rd CGPM
Declaration on the unit of mass and on the definition of weight; conventional value of gn
Taking into account the decision of the Comité International des Poids et Mesures of
Taking into account the decision contained in the sanction of the prototypes of the Metric System, unanimously accepted by the Conférence Générale des Poids et Mesures on
Considering the necessity to put an end to the ambiguity which in current practice still exists on the meaning of the word weight, used sometimes for mass, sometimes for mechanical force;
The Conference declares
- The kilogram is the unit of mass; it is equal to the mass of the international prototype of the kilogram;
- The word "weight" denotes a quantity of the same nature as a "force": the weight of a body is the product of its mass and the acceleration due to gravity; in particular, the standard weight of a body is the product of its mass and the standard acceleration due to gravity;
- The value adopted in the International Service of Weights and Measures for the standard acceleration due to gravity is
980.665 cm/s2,value already stated in the laws of some countries.
This value of gn was the conventional reference for calculating the now obsolete unit kilogram force.