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Created page with 'File:lighterstill.jpg ==Etymology== [http://nordan.daynal.org/wiki/index.php?title=English#ca._1100-1500_.09THE_MIDDLE_ENGLISH_PERIOD Middle English] spede, from [http://nor...'
[[File:lighterstill.jpg]]
==Etymology==
[http://nordan.daynal.org/wiki/index.php?title=English#ca._1100-1500_.09THE_MIDDLE_ENGLISH_PERIOD Middle English] spede, from [http://nordan.daynal.org/wiki/index.php?title=English#ca._600-1100.09THE_OLD_ENGLISH.2C_OR_ANGLO-SAXON_PERIOD Old English] spēd; akin to Old High German spuot prosperity, speed, Old English spōwan to succeed, [[Latin]] spes [[hope]], Lithuanian spėti to be in [[time]]
*Date: before [http://www.wikipedia.org/wiki/12th_Century 12th century]
==Definitions==
*1 archaic : prosperity in an undertaking : success
*2 a : the act or state of moving swiftly : swiftness b : rate of motion: as (1) : velocity 1 (2) : the magnitude of a velocity irrespective of direction c : impetus
*3 : swiftness or rate of performance or action : velocity 3a
*4 a : the sensitivity of a photographic film, plate, or paper expressed numerically b : the light-gathering power of a lens or optical system c : the time during which a camera shutter is open
*5 : a transmission gear in automotive vehicles or bicycles —usually used in combination <a ten-speed bicycle>
*6 : someone or something that appeals to one's taste <just my speed>
*7 : methamphetamine; also : a related stimulant drug and especially an amphetamine
==Description==
In kinematics, the instantaneous [[speed]] of an object (denoted v) is the [[magnitude]] of its instantaneous [[velocity]] (the rate of [[change]] of its position); it is thus the [http://en.wikipedia.org/wiki/Scalar_(physics) scalar] [[equivalent]] of [[velocity]]. The [[average]] speed of an object in an [[interval]] of [[time]] is the distance [[traveled]] by the object divided by the duration of the interval; the instantaneous speed is the [[limit]] of the [[average]] speed as the duration of the time interval approaches zero .
Like [[velocity]], speed has the [[dimensions]] of a length divided by a [[time]]; the [http://en.wikipedia.org/wiki/International_System_of_Units SI unit] of speed is the [http://en.wikipedia.org/wiki/Meter_per_second meter per second], but the most usual [[unit]] of speed in everyday usage is the [http://en.wikipedia.org/wiki/Kilometer_per_hour kilometer per hour] or, in certain countries, the [http://en.wikipedia.org/wiki/Mile_per_hour mile per hour].
The fastest possible speed at which [[energy]] or [[information]] can [[travel]], according to [http://en.wikipedia.org/wiki/Special_relativity special relativity], is the [[speed of light]] in vacuum c = 299,792,458 meters per second, approximately 1079 million kilometers (671 million miles) per hour. [[Matter]] cannot quite reach the [[speed of light]], as this would require an [[infinite]] amount of [[energy]].[http://en.wikipedia.org/wiki/Speed
The instantaneous speed v is defined as the magnitude of the instantaneous [[velocity]] v, that is the derivative of the position r with respect to [[time]]:
[[File:Speed_1b.jpg]]
If s is the length of the path traveled until time t, the speed equals the time derivative of s:
[[File:Speed_2.jpg ]]
[[Category: Physics]]
==Etymology==
[http://nordan.daynal.org/wiki/index.php?title=English#ca._1100-1500_.09THE_MIDDLE_ENGLISH_PERIOD Middle English] spede, from [http://nordan.daynal.org/wiki/index.php?title=English#ca._600-1100.09THE_OLD_ENGLISH.2C_OR_ANGLO-SAXON_PERIOD Old English] spēd; akin to Old High German spuot prosperity, speed, Old English spōwan to succeed, [[Latin]] spes [[hope]], Lithuanian spėti to be in [[time]]
*Date: before [http://www.wikipedia.org/wiki/12th_Century 12th century]
==Definitions==
*1 archaic : prosperity in an undertaking : success
*2 a : the act or state of moving swiftly : swiftness b : rate of motion: as (1) : velocity 1 (2) : the magnitude of a velocity irrespective of direction c : impetus
*3 : swiftness or rate of performance or action : velocity 3a
*4 a : the sensitivity of a photographic film, plate, or paper expressed numerically b : the light-gathering power of a lens or optical system c : the time during which a camera shutter is open
*5 : a transmission gear in automotive vehicles or bicycles —usually used in combination <a ten-speed bicycle>
*6 : someone or something that appeals to one's taste <just my speed>
*7 : methamphetamine; also : a related stimulant drug and especially an amphetamine
==Description==
In kinematics, the instantaneous [[speed]] of an object (denoted v) is the [[magnitude]] of its instantaneous [[velocity]] (the rate of [[change]] of its position); it is thus the [http://en.wikipedia.org/wiki/Scalar_(physics) scalar] [[equivalent]] of [[velocity]]. The [[average]] speed of an object in an [[interval]] of [[time]] is the distance [[traveled]] by the object divided by the duration of the interval; the instantaneous speed is the [[limit]] of the [[average]] speed as the duration of the time interval approaches zero .
Like [[velocity]], speed has the [[dimensions]] of a length divided by a [[time]]; the [http://en.wikipedia.org/wiki/International_System_of_Units SI unit] of speed is the [http://en.wikipedia.org/wiki/Meter_per_second meter per second], but the most usual [[unit]] of speed in everyday usage is the [http://en.wikipedia.org/wiki/Kilometer_per_hour kilometer per hour] or, in certain countries, the [http://en.wikipedia.org/wiki/Mile_per_hour mile per hour].
The fastest possible speed at which [[energy]] or [[information]] can [[travel]], according to [http://en.wikipedia.org/wiki/Special_relativity special relativity], is the [[speed of light]] in vacuum c = 299,792,458 meters per second, approximately 1079 million kilometers (671 million miles) per hour. [[Matter]] cannot quite reach the [[speed of light]], as this would require an [[infinite]] amount of [[energy]].[http://en.wikipedia.org/wiki/Speed
The instantaneous speed v is defined as the magnitude of the instantaneous [[velocity]] v, that is the derivative of the position r with respect to [[time]]:
[[File:Speed_1b.jpg]]
If s is the length of the path traveled until time t, the speed equals the time derivative of s:
[[File:Speed_2.jpg ]]
[[Category: Physics]]