
A physical quantity is either a quantity within physics that can be measured (e.g. mass, volume, etc.), or it is the result of measurement and usually expressed as the product (mathematics) of a number and a physical unit (whereby SI unit are usually preferred). ==Example== : ''P'' = 42.3 x 103 W = 42.3 kW where ''P'' represents the physical quantity of Power (physics) ''42.3 x 103'' is the numerical value ''k'' is the SI prefix ''kilo'' representing 103 ''W'' is the symbol for the SI derived unit of power, the watt ''kW'' is the kilowatt (= 103W) ==Subscripted variables== Usually, the symbols for physical quantities are chosen to be a single letter of the Latin alphabet or Greek alphabet, printed in italic. Both lower and capital letters are used. Often, the symbols are modified by subscripts or superscripts. If these sub- or superscripts are themselves symbols for physical quantities or numbers, they are printed in italic. Other sub- and superscripts are printed upright (roman). ===Examples=== * ''E''p for potential energy (note: p is upright) * ''cp'' for heat capacity at constant pressure (note: ''p'' represents the physical quantity of pressure and is therefore printed italic) ==Extensive vs Intensive== A quantity is called: * ''extensive quantity'' when its magnitude is additive for subsystems (e.g. volume V or the mass m) * ''intensive quantity'' where the magnitude is independent of the extent of the system (e.g. temperature T, pressure ''p'') ==Prefixes== Some extensive physical quantities may be prefixed to qualify the meaning: * ''specific'' is added to refer to ''the quantity divided by its mass'' * ''molar'' is added to refer to ''the quantity divided by amount of substance'' ===Examples=== * the specific volume ''v'' = ''V/m'' * the molar volume ''V''m = ''V''/''n'' ==See also== * List of physical quantities * Physical unit * SI * International standard ISO 31: Quantities and units Introductory physics Physical quantity vi:Đại lượng vật lý
This category identifies Physical quantity which can be manipulated or measured by a Physicist Measurement Physics vi:Category:Đại lượng vật lý zh-cn:category:物理量
Shouldn't this be at :Category:Physical quantities (note plural)? --User:Diberri | User talk:Diberri 05:56, Jul 14, 2004 (UTC) : At [http://en.wikipedia.org/wiki/Wikipedia:Categorization#General_naming_conventions] we are encouraged to use the singular wherever possible. User:Icairns 11:14, 14 Jul 2004 (UTC) :: I interpreted that page to say that only broad topics should have singular category names (such as :Category:Science or :Category:Medicine). I see ''physical quantities'' as more of an enumeration of said quantities, so I would suppose that the category name should be plural. --User:Diberri | User talk:Diberri 16:50, Jul 14, 2004 (UTC) ::: Quoting from the above link: ''Topical category names should be singular. Examples: "Biology", "Law".'' I presume that the implied choice is between categories named, eg, either Law or Laws. The recommendation (or instruction?), as I understand it, is to keep these singular. In the same way, we are faced with a category to be called Physical quantity or Physical quantities. I took the direction to imply usage of the name: Physical quantity. I would imagine a category devoted to the 'List of physical quantities' would be plural - however, there is already an article List of physical quantities 17:33, 14 Jul 2004 (UTC) :::: I think we're interpreting the policy in different ways. To me, :Category:Law and :Category:Laws are ''very'' different, not just because one is singular and the other is plural. The former (singular ''law'') is intended to capture broad topics relating to law, like family law, Chinese law, and case law. The latter (plural ''laws'') is meant for individual laws, like Occam's razor and Boyle's law. Thus :Category:Physical quantities would be for individual physical quantities, like momentum, force, and torque. There is no such topic as "physical quantity", and so I would presume that such a category should not exist, and should be replaced with its plural name. --User:Diberri | User talk:Diberri 18:25, Jul 14, 2004 (UTC) Category:Physical quantities would be a list of specific times, torques, masses, and angles etc. Category:Physical quantity, however, is a list of ways of measuring physical quantities (not specific measurements), and is a list including time, torque, mass, and angle. So: *This category is correct in the singular *Since there are not usually articles for physical quantities, such a category would be little used (for instance Right angle redirects to angle). :: Sorry to interrupt, but I'm afraid I don't understand your logic. You seem to be advocating the use of ''physical quantity'' as a list of items, but then conclude that the category should be named in the singular. However, the Wikipedia:Categorization#General naming conventions states that ''Category names for lists of items should be plural''. Thus, we should have :Category:Physical quantities (i.e. ''plural'') instead. --User:Diberri | User talk:Diberri 21:48, Jul 14, 2004 (UTC) What is the difference between Physical quantity and Measurement? User:Hyacinth 19:28, 14 Jul 2004 (UTC) : For me, Physical quantity (e.g. momentum, force, etc) is an aspect of the real or physical world around us that is capable of being measured. Measurement is one or more estimates of the value of a physical quantity in a particular context (cf: a 'result' in an experiment) - A measurement involves a value and a unit of measurement. Confusingly, Measurement is also the topic of taking measurements. Others may differ. User:Icairns 19:50, 14 Jul 2004 (UTC)
See other meanings of words starting from letter:
Words begining with Physical_quantity:
Physical_quantity
Physical_quantity
Physical_quantity
Physical quantity
A physical quantity is either a quantity within physics that can be measured (e.g. mass, volume, etc.), or it is the result of measurement and usually expressed as the product (mathematics) of a number and a physical unit (whereby SI unit are usually preferred). ==Example== : ''P'' = 42.3 x 103 W = 42.3 kW where ''P'' represents the physical quantity of Power (physics) ''42.3 x 103'' is the numerical value ''k'' is the SI prefix ''kilo'' representing 103 ''W'' is the symbol for the SI derived unit of power, the watt ''kW'' is the kilowatt (= 103W) ==Subscripted variables== Usually, the symbols for physical quantities are chosen to be a single letter of the Latin alphabet or Greek alphabet, printed in italic. Both lower and capital letters are used. Often, the symbols are modified by subscripts or superscripts. If these sub- or superscripts are themselves symbols for physical quantities or numbers, they are printed in italic. Other sub- and superscripts are printed upright (roman). ===Examples=== * ''E''p for potential energy (note: p is upright) * ''cp'' for heat capacity at constant pressure (note: ''p'' represents the physical quantity of pressure and is therefore printed italic) ==Extensive vs Intensive== A quantity is called: * ''extensive quantity'' when its magnitude is additive for subsystems (e.g. volume V or the mass m) * ''intensive quantity'' where the magnitude is independent of the extent of the system (e.g. temperature T, pressure ''p'') ==Prefixes== Some extensive physical quantities may be prefixed to qualify the meaning: * ''specific'' is added to refer to ''the quantity divided by its mass'' * ''molar'' is added to refer to ''the quantity divided by amount of substance'' ===Examples=== * the specific volume ''v'' = ''V/m'' * the molar volume ''V''m = ''V''/''n'' ==See also== * List of physical quantities * Physical unit * SI * International standard ISO 31: Quantities and units Introductory physics Physical quantity vi:Đại lượng vật lý
Physical quantity
This category identifies Physical quantity which can be manipulated or measured by a Physicist Measurement Physics vi:Category:Đại lượng vật lý zh-cn:category:物理量
Physical quantity
Shouldn't this be at :Category:Physical quantities (note plural)? --User:Diberri | User talk:Diberri 05:56, Jul 14, 2004 (UTC) : At [http://en.wikipedia.org/wiki/Wikipedia:Categorization#General_naming_conventions] we are encouraged to use the singular wherever possible. User:Icairns 11:14, 14 Jul 2004 (UTC) :: I interpreted that page to say that only broad topics should have singular category names (such as :Category:Science or :Category:Medicine). I see ''physical quantities'' as more of an enumeration of said quantities, so I would suppose that the category name should be plural. --User:Diberri | User talk:Diberri 16:50, Jul 14, 2004 (UTC) ::: Quoting from the above link: ''Topical category names should be singular. Examples: "Biology", "Law".'' I presume that the implied choice is between categories named, eg, either Law or Laws. The recommendation (or instruction?), as I understand it, is to keep these singular. In the same way, we are faced with a category to be called Physical quantity or Physical quantities. I took the direction to imply usage of the name: Physical quantity. I would imagine a category devoted to the 'List of physical quantities' would be plural - however, there is already an article List of physical quantities 17:33, 14 Jul 2004 (UTC) :::: I think we're interpreting the policy in different ways. To me, :Category:Law and :Category:Laws are ''very'' different, not just because one is singular and the other is plural. The former (singular ''law'') is intended to capture broad topics relating to law, like family law, Chinese law, and case law. The latter (plural ''laws'') is meant for individual laws, like Occam's razor and Boyle's law. Thus :Category:Physical quantities would be for individual physical quantities, like momentum, force, and torque. There is no such topic as "physical quantity", and so I would presume that such a category should not exist, and should be replaced with its plural name. --User:Diberri | User talk:Diberri 18:25, Jul 14, 2004 (UTC) Category:Physical quantities would be a list of specific times, torques, masses, and angles etc. Category:Physical quantity, however, is a list of ways of measuring physical quantities (not specific measurements), and is a list including time, torque, mass, and angle. So: *This category is correct in the singular *Since there are not usually articles for physical quantities, such a category would be little used (for instance Right angle redirects to angle). :: Sorry to interrupt, but I'm afraid I don't understand your logic. You seem to be advocating the use of ''physical quantity'' as a list of items, but then conclude that the category should be named in the singular. However, the Wikipedia:Categorization#General naming conventions states that ''Category names for lists of items should be plural''. Thus, we should have :Category:Physical quantities (i.e. ''plural'') instead. --User:Diberri | User talk:Diberri 21:48, Jul 14, 2004 (UTC) What is the difference between Physical quantity and Measurement? User:Hyacinth 19:28, 14 Jul 2004 (UTC) : For me, Physical quantity (e.g. momentum, force, etc) is an aspect of the real or physical world around us that is capable of being measured. Measurement is one or more estimates of the value of a physical quantity in a particular context (cf: a 'result' in an experiment) - A measurement involves a value and a unit of measurement. Confusingly, Measurement is also the topic of taking measurements. Others may differ. User:Icairns 19:50, 14 Jul 2004 (UTC)
See other meanings of words starting from letter:
P
PA | PB | PC | PD | PE | PF | PG | PH | PI | PJ | PK | PL | PM | PN | PO | PR | PS | PT | PU | PW | PX | PY | PZ |Words begining with Physical_quantity:
Physical_quantity
Physical_quantity
Physical_quantity
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