|
Difference between
version 10
and
version 6:
| Line 16 was replaced by line 16 |
| - * [Wikipedia on "Physical Units"|http://en.wikipedia.org/wiki/Physical_unit]. Some interesting sentences: "Units as Dimensions: Any value of a physical quantity is expressed as a comparison to a unit of that quantity. For example, the value of a physical quantity Q is written as the product of a unit [Q] and a numerical factor: Q = n * [Q] = n[Q]. The multiplication sign is usually left out, just as it is left out between variables in scientific notation of formulas. In formulas the unit [Q] can be treated as if it was a kind of physical dimension: see dimensional analysis for more on this treatment. A distinction should be made between units and standards. A unit is fixed by its definition, and is independent of physical conditions such as temperature. By contrast, a standard is a physical realization of a unit, and realizes that unit only under certain physical conditions. For example, the metre is a unit, while a metal bar is a standard. One metre is the same length regardless of temperature, but a metal bar will be one metre long only at a certain temperature. For most quantities a unit is absolutely necessary to communicate values of that physical quantity. For example, conveying to someone a particular length without using some sort of unit is impossible, because a length cannot be described without a reference used to make sense of the value given." |
| + * [Wikipedia on "Physical Units"|http://en.wikipedia.org/wiki/Physical_unit]. Some interesting sentences: "Units as Dimensions: Any value of a physical quantity is expressed as a comparison to a unit of that quantity. For example, the value of a physical quantity Q is written as the product of a unit [[Q] and a numerical factor: Q = n * [[Q] = n[[Q]. The multiplication sign is usually left out, just as it is left out between variables in scientific notation of formulas. In formulas the unit [[Q] can be treated as if it was a kind of physical dimension: see dimensional analysis for more on this treatment. A distinction should be made between units and standards. A unit is fixed by its definition, and is independent of physical conditions such as temperature. By contrast, a standard is a physical realization of a unit, and realizes that unit only under certain physical conditions. For example, the metre is a unit, while a metal bar is a standard. One metre is the same length regardless of temperature, but a metal bar will be one metre long only at a certain temperature. For most quantities a unit is absolutely necessary to communicate values of that physical quantity. For example, conveying to someone a particular length without using some sort of unit is impossible, because a length cannot be described without a reference used to make sense of the value given." |
| Line 22 was replaced by line 22 |
| - * [Wikipedia on "Quantity"|http://en.wikipedia.org/wiki/Quantity]. "Quantity is a generic term used when referring to the measurement (count, amount) of a scalar, vector, number of items or to some other way of denominating the value of a collection or group of items. It is usually represented as a number (numeric value) of units together with the type of those units (if required) and a referent defining the nature of the collection. Both parts are required." |
| + * [Wikipedia on "Quantity"|http://en.wikipedia.org/wiki/Quantity]. "Quantity is a generic term used when referring to the measurement (count, amount) of a scalar, vector, number of items or to some other way of denominating the value of a collection or group of items. It is usually represented as a number (numeric value) of units together with the type of those units (if required) and a referent defining the nature of the collection. Both parts are required. Examples are: one apple, two apples, three apples, where the number is an integer so does not require a type; 1.76 litres (liters) of milk; 500 people" |
Back to KRSMS Measurement,
or to the Page History.
|
