Dictionary Definition
acceleration
Noun
1 an increase in speed; "modern science caused an
acceleration of cultural change" [ant: deceleration]
2 the act of accelerating; increasing the speed
[syn: quickening,
speedup]
3 (physics) a rate of change of velocity
User Contributed Dictionary
English
Etymology
 Latin acceleratio; compare French accélération
 accelerate + tion
Pronunciation
 əksĕlərā'shən, /ək.sɛl.əˈreɪ.ʃən/, /@ksEl@"reIS@n/
 Rhymes: eɪʃǝn
Noun
 (uncountable) The act of accelerating, or the state of being
accelerated; increase of motion or action; as opposed to retardation or deceleration.
 a falling body moves toward the earth with an acceleration of velocity
 (countable) The amount by which a speed or velocity increases (and so a
scalar
quantity or a vector
quantity).
 The boosters produce an acceleration of 20 metres per second per second.
 Quotations

 A period of social improvement, or of intellectual advancement, contains within itself a principle of acceleration — I. Taylor
 The change of velocity with respect to time (can include deceleration or changing direction).
Usage notes
Acceleration in SI units is measured in metres per second per second (m/s2), or in imperial units in feet per second per second (ft/s2).Antonyms
 (act, state, amount): deceleration, retardation
Translations
act, state
 Croatian: akceleracija, ubrzanje
 Czech: zrychlení
 Dutch: versnelling, acceleratie
 Finnish: kiihdytys
 French: accélération
 German: Beschleunigung
 Hebrew: האצה (he'atza)
 Interlingua: acceleration
 Italian: accelerazione
 Japanese: 加速 (かそく, kasoku)
 Norwegian: akselerasjon
 Polish: przyspieszenie, akceleracja
 Portuguese: aceleração
 Romanian: acceleraţie
 Russian: ускорение, разгон
 Spanish: aceleración
 Swedish: acceleration
amount
(physics)
 Croatian: akceleracija, ubrzanje
 Czech: zrychlení
 Dutch: versnelling, acceleratie
 Finnish: kiihtyvyys
 French: accélération
 German: Beschleunigung
 Hebrew: תאוצה
 Italian: accelerazione
 Polish: przyspieszenie
 Russian: ускорение
 Slovene: pospešek
 Swedish: acceleration
 Urdu: اسراع (israa)
 ttbc Indonesian: percepatan
See also
Interlingua
Noun
acceleration acceleration
Swedish
Noun
 acceleration; a change in velocity
Extensive Definition
In physics, acceleration is defined as the
rate of
change of velocity,
or as the second derivative of position (with
respect to time). It is then a vector
quantity with dimension length/time². In SI units, acceleration
is measured in
meters/second² (m·s2). The term "acceleration" generally
refers to the rate of change in instantaneous velocity. (velocity
is speed and direction)
In common speech, the term acceleration is only
used for an increase in speed; a decrease in speed is called
deceleration. In physics, any increase or decrease in speed is
referred to as acceleration and similarly, motion in a circle at
constant speed is also an acceleration, since the direction
component of the velocity is changing. See also Newton's
Laws of Motion.
Relation to relativity
After completing his theory of special relativity, Albert Einstein realized that forces felt by objects undergoing constant proper acceleration are indistinguishable from those in a gravitational field. This was the basis for his development of general relativity, a relativistic theory of gravity. This is also the basis for the popular Twin paradox, which asks why one twin ages less when moving away from his sibling at near lightspeed and then returning, since the nonaging twin can say that it is the other twin that was moving. General relativity solved the "why does only one object feel accelerated?" problem which had plagued philosophers and scientists since Newton's time (and caused Newton to endorse absolute space). In special relativity, only inertial frames of reference (nonaccelerated frames) can be used and are equivalent; general relativity considers all frames, even accelerated ones, to be equivalent. (The path from these considerations to the full theory of general relativity is traced in the Introduction to general relativity.)Formula
The formula for the average acceleration over a time period \Delta t is \mathbf=\frac
 \mathbf(t+\Delta t) is the final velocity
 \mathbf(t) is the initial velocity
 \mathbf is the initial time and \Delta \mathbf is the change in time
The formula for the instantaneous acceleration at
time t is
 \mathbf(t)=\lim_\frac=\frac
One should also note that the average and
instantaneous accelerations over a time period \Delta t=t_1t_0 are
related through the Mean
Value Theorem for Integrals:
 \bar\int_^\mathrmt=\int_^\mathbf(t)\mathrmt
Putting it all together means:
 \mathbf = \frac = \frac
 \mathbf is acceleration
 \mathbf is velocity
 \mathbf is position
 is time
See also
External links
 Acceleration and Free Fall  a chapter from an online textbook
 Trajectories and Radius, Velocity, Acceleration on Project PHYSNET (ERROR  PAGE MOVED)
 Science aid: Movement
 Physics Classroom: Acceleration
 Science.dirbix: Acceleration
 Acceleration Calculator
 Motion Characteristics for Circular Motion
acceleration in Afrikaans: Versnelling
acceleration in Arabic: تسارع
acceleration in Asturian: Aceleración
acceleration in Bengali: ত্বরণ
acceleration in Min Nan: Kasoktō͘
acceleration in Belarusian: Паскарэнне
acceleration in Bosnian: Ubrzanje
acceleration in Bulgarian: Ускорение
acceleration in Catalan: Acceleració
acceleration in Czech: Zrychlení
acceleration in Welsh: Cyflymiad
acceleration in Danish: Acceleration
acceleration in German: Beschleunigung
acceleration in Estonian: Kiirendus
acceleration in Modern Greek (1453):
Επιτάχυνση
acceleration in Spanish: Aceleración
acceleration in Esperanto: Akcelo
acceleration in Basque: Azelerazio
acceleration in Persian: شتاب
acceleration in French: Accélération
acceleration in Irish: Luasghéarú
acceleration in Manx: Bieauaghey
acceleration in Galician: Aceleración
acceleration in Hakka Chinese: Kâsukthu
acceleration in Korean: 가속도
acceleration in Croatian: Ubrzanje
acceleration in Ido: Acelero
acceleration in Indonesian: Percepatan
acceleration in Icelandic: Hröðun
acceleration in Italian: Accelerazione
acceleration in Hebrew: תאוצה
acceleration in Latin: Acceleratio
acceleration in Latvian: Paātrinājums
acceleration in Lithuanian: Pagreitis
acceleration in Hungarian: Gyorsulás
acceleration in Malayalam: ത്വരണം
acceleration in Malay (macrolanguage):
Pecutan
acceleration in Mongolian: Хурдатгал
acceleration in Dutch: Versnelling
(natuurkunde)
acceleration in Japanese: 加速度
acceleration in Norwegian: Akselerasjon
acceleration in Norwegian Nynorsk:
Akselerasjon
acceleration in Novial: Akseleratione
acceleration in Polish: Przyspieszenie
acceleration in Portuguese: Aceleração
acceleration in Quechua: P'ikwachiy
acceleration in Russian: Ускорение
acceleration in Sicilian: Accilirazzioni
acceleration in Simple English:
Acceleration
acceleration in Slovak: Zrýchlenie
acceleration in Slovenian: Pospešek
acceleration in Serbian: Убрзање
acceleration in SerboCroatian: Ubrzanje
acceleration in Finnish: Kiihtyvyys
acceleration in Swedish: Acceleration
acceleration in Telugu: త్వరణము
acceleration in Thai: ความเร่ง
acceleration in Vietnamese: Gia tốc
acceleration in Turkish: İvme
acceleration in Ukrainian: Прискорення
acceleration in Chinese: 加速度
Synonyms, Antonyms and Related Words
accelerando, aggravation, beefingup,
blowing up, blowup,
concentration,
condensation,
consolidation,
deepening, double
time, doublequick, doublequick time, drive, enhancement, exacerbation, exaggeration, explosion, festination, forced march,
forwarding, getaway, hastening, heatingup,
heightening,
hurrying, impetus, information explosion,
intensification,
magnification,
pickup, population
explosion, quickening, redoubling, reinforcement, speeding, speedup, stepup, strengthening, thrust, tightening