− 
In [[physics]], '''acceleration''' is the [[Rate (mathematics)rate]] at which the [[velocity]] of a body changes with time.<ref>{{cite booktitle=The Principles of Mechanicsfirst=Henrylast=Crewpublisher=BiblioBazaar, LLCyear=2008isbn=0559368712pages=43}}</ref> [[Velocity]] and acceleration are [[Euclidean vectorvector]] quantities, with [[magnitude (mathematics)magnitude]], [[direction (geometry)direction]], and add according to the [[parallelogram law]].<ref>{{cite booktitle=Relativity and Common Sensefirst=Hermannlast=Bondipages=3publisher=Courier Dover Publicationsyear=1980isbn=0486240215}}</ref><ref>{{cite booktitle=Physics the Easy Waypages=27first=Robert L.last=Lehrmanpublisher=Barron's Educational Seriesyear=1998isbn=0764102362}}</ref> As described by [[Newton's Second Law]], acceleration is caused by a net [[force]]; the force, as a vector, is equal to the product of the mass of the object being accelerated (scalar) and the acceleration (vector). The [[International System of UnitsSI]] unit for acceleration is the [[metre per second squared]] (m/s<sup>2</sup>). 
+ 
In my house there are donuts and popsicles. I eat food and my bedroom has pink ponies in it which involves the [[physics]], '''acceleration''' is the [[Rate (mathematics)rate]] at which the [[velocity]] of a body changes with time.<ref>{{cite booktitle=The Principles of Mechanicsfirst=Henrylast=Crewpublisher=BiblioBazaar, LLCyear=2008isbn=0559368712pages=43}}</ref> [[Velocity]] and acceleration are [[Euclidean vectorvector]] quantities, with [[magnitude (mathematics)magnitude]], [[direction (geometry)direction]], and add according to the [[parallelogram law]].<ref>{{cite booktitle=Relativity and Common Sensefirst=Hermannlast=Bondipages=3publisher=Courier Dover Publicationsyear=1980isbn=0486240215}}</ref><ref>{{cite booktitle=Physics the Easy Waypages=27first=Robert L.last=Lehrmanpublisher=Barron's Educational Seriesyear=1998isbn=0764102362}}</ref> As described by [[Newton's Second Law]], acceleration is caused by a net [[force]]; the force, as a vector, is equal to the product of the mass of the object being accelerated (scalar) and the acceleration (vector). The [[International System of UnitsSI]] unit for acceleration is the [[metre per second squared]] (m/s<sup>2</sup>). 

For example, an object such as a car that starts from standstill, then travels in a straight line at increasing speed, is accelerating in the direction of travel. If the car changes direction at constant speedometer reading, there is strictly speaking an acceleration although it is often not so described; passengers in the car will experience a force pushing them back into their seats in linear acceleration, and a sideways force on changing direction. If the speed of the car decreases, it is usual and meaningful to speak of '''deceleration'''; mathematically it is acceleration in the opposite direction to that of motion. 

For example, an object such as a car that starts from standstill, then travels in a straight line at increasing speed, is accelerating in the direction of travel. If the car changes direction at constant speedometer reading, there is strictly speaking an acceleration although it is often not so described; passengers in the car will experience a force pushing them back into their seats in linear acceleration, and a sideways force on changing direction. If the speed of the car decreases, it is usual and meaningful to speak of '''deceleration'''; mathematically it is acceleration in the opposite direction to that of motion. 