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A kip is a US customary unit of force. It equals 1000 pounds-force , and is used primarily by structural engineers to indicate forces where the value represented in pound-force is inefficient. Although uncommon, it is occasionally also considered a unit of mass , equal to 1000 pounds (i.e. one half of a short ton ).
Units for other physical quantities are derived from this set as needed. In English Engineering Units, the pound-mass and the pound-force are distinct base units, and Newton's Second Law of Motion takes the form = where is the acceleration in ft/s 2 and g c = 32.174 lb·ft/(lbf·s 2).
Avoirdupois is a system of mass based on a pound of 16 ounces, while Troy weight is the system of mass where 12 troy ounces equals one troy pound. The symbol g 0 is used to denote standard gravity in order to avoid confusion with the (upright) g symbol for gram.
Metrology is a wide reaching field, but can be summarized through three basic activities: the definition of internationally accepted units of measurement, the realisation of these units of measurement in practice, and the application of chains of traceability (linking measurements to reference standards).
The SI units are defined by declaring that seven defining constants [1]: 125–129 have certain exact numerical values when expressed in terms of their SI units. The realisation of the definition of a unit is the procedure by which the definition may be used to establish the value and associated uncertainty of a quantity of the same kind as the ...
Since all gases have the same volume per mole at a given temperature and pressure far from their points of liquefaction and solidification (see Perfect gas), and air is about 1 / 5 oxygen (molecular mass 32) and 4 / 5 nitrogen (molecular mass 28), the density of any near-perfect gas relative to air can be obtained to a good ...
Measure of magnetism, taking account of the strength and the extent of a magnetic field: weber (Wb) L 2 M T −2 I −1: scalar Mass fraction: x: Mass of a substance as a fraction of the total mass kg/kg 1: intensive (Mass) Density (or volume density) ρ: Mass per unit volume kg/m 3: L −3 M: intensive Mean lifetime: τ: Average time for a ...
Conversion of units is the conversion of the unit of measurement in which a quantity is expressed, typically through a multiplicative conversion factor that changes the unit without changing the quantity. This is also often loosely taken to include replacement of a quantity with a corresponding quantity that describes the same physical property.