AGMA 904-C96-1996 pdf free.Metric Usage.
2.5.1 Weight. Considerable confusion exists in the use of the term weight as quantity to mean either gravitational force or mass. In commercial and everyday use, the term weight nearly always means mass; thus, when one speaks of a person’s weight, the quantity referred to is mass.
In science and technology, the term weight of a body has usually meant the force that if applied to the body would give it an acceleration equal to the local acceleration of free fall.
Because of the dual use of the term weight as both a force and a mass, this term should be avoided in technical practice.
To ensure complete understanding we should use the terms mass and force in place of weight.
It should be understood that where the term weight is used in machine specifications, etc., it has meant mass and to provide clarity in these uses for the general public we should specify mass followed by weight in parenthesis and specify the value in grams or kilograms. Example: Machine mass (weight) 1 500 kilograms.
2.5.2 Mass. In engineering calculations involving structures, vehicles, or machines on the surface of the earth, the mass in kilograms is multiplied by 9.8 to obtain the approximate force of gravity in newtons. (The force of gravity acting on a mass of I kilogram varies from about 9.77 newtons to 9.83 newtons in various parts of the world).
2.6 Rules for Vriting SI Symbols.
2.6.1 SI Symbols (see Table 9— 1 for SI computer symbols):
(1) Shall be printed in roman (upright) type regardless of the type used in the rest of the text (2) Shall be written in lower—case letters except that the first letter is written in upper case when the name of (he unit is derived from a proper name, and the symbol for liter is a capital L See Tables 2— I through 2—5. Examples: m meter. s second. A ampere. Wb weher
(3) Shall remain unaltered in the plural
(4) Shall be written without a final full stop (period) except at the end of a sentence
(5) Shall be placed after the complete numerical value in the expression for a quantity, leaving a space between the numerical value and the first letter of the symbol
Example: 32 Im. not 321m. for 32 lumens
(6) Symbols are the same in all languages
2.6.2 Prdctice. It is recommended that the symbols for SI units, and not written words. be used in written text: e.g.. 16 m@. not 16 square meters. Spelled—out unit names and prefixes are treated as common nouns in English. Thus, the first letter of a unit name is not capitalized except at the beginning of a sentence or in capitalized material such as a title. An exception to this is degree Celsius. The unit name is degree and modified by the adjective Celsius and is written degree Celsius.
In text, a symbol should not be used to start a sentence.
2.7 Units Formed by Multiplication and I)hislon.
2.7.1 MultiplicatIon. The product of two or more units in symbolic form can be indicated by a dot. In the international recommendation the dot may be dispensed with when there is no risk of confusion with any other symbol. The dot may be placed on the line if the preferred position cannot be produced as on a computer printout, or an asterisk may be used.AGMA 904 pdf download.