Quantity

:For the use in linguistics, see length (phonetics).

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Quantity is a general term used to refer to any type of quantitative property or attribute, such as mass, length, or time. A particular quantity is a magnitude of a scalar or vector quantity. The term quantity is also often used to refer to denumerable (countable) collections of objects.

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A given quantity is usually represented either as a number of units, together with the type of those units, or a number of objects with a referent defining the type of object. Thus, Scalar quantities such as mass, and vector quantities such as force, are continuous quantities and are usually represented as a multiple of a real number and a unit of continuous quantity, such as a gram or newton. A count of a denumerable collection of entities is represented as an integer and the type of object or entity, such as an apple or a set. A number, including a particular measurement, is not by itself a quantity.

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Examples are

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• 1.76 litres (liters) of milk, which is continuous quantity
• $2\; pi\; r$ metres, where r is the length of a radius of a circle expressed in metres (or meters)
• one apple, two apples, three apples, where the number is an integer representing the count of a denumerable collection of objects (apples)
• 500 people (also involving a count)

Where the count is one then the indefinite article may be used (for example, a car) and similar alternatives exist for other particular counts (for example, a brace of pheasant, a dozen eggs).

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Quantification in its very simplest sense can be found in statements such as "A is greater than B". In the example cited, an expression is made that A has a greater quantity of something (such as volume or charisma) than B; and that if A and B were placed in an ordered set, then A would come after B if the order is arranged on an increasing (rather than decreasing) scale.

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Quantity: See also: ►



 

Mass: Mass is a property of physical objects that, roughly speaking, measures the amount of matter they contain. It is a central concept of classical mechanics and related subjects....

Length: In general English usage, length (symbols: l, L) is but one particular instance of distance – an object's length is how long the object is – but in the physical sciences and engineering, the word length is in some contexts used synonymously with "distance". Height is vertical distance; ...

Time: :For alternate uses of "time", see Time (disambiguation) or see TIME (magazine)....