Kinetic energy

In <a href="/facts/Physics/a7aH2y08">physics</a>, the kinetic energy of an object is the form of <a href="/facts/Energy/wd8PrQM7">energy</a> that it possesses due to its <a href="/facts/Motion_(physics)/dCnP7MlB">motion</a>.
In <a href="/facts/Classical_mechanics/ykG8upsN">classical mechanics</a>, the kinetic energy of a non-rotating object of <a href="/facts/Mass/HHdc8XmF">mass</a> m traveling at a <a href="/facts/Speed/I3qgMPfs">speed</a> v is 
 
 
 
 
 
 1
 2
 
 
 m
 
 v
 
 2
 
 
 
 
 {\textstyle {\frac {1}{2}}mv^{2}}
 
. 
The kinetic energy of an object is equal to the <a href="/facts/Work_(physics)/mbclFPBs">work</a>, or force (<a href="/facts/Force/LNAUWMwK">F</a>) in the direction of motion times its displacement (<a href="/facts/Displacement_(geometry)/jkmEfS3C">s</a>), needed to accelerate the object from <a href="/facts/Rest_(physics)/bzK9uzI2">rest</a> to its given speed. The same amount of work is done by the object when decelerating from its current <a href="/facts/Speed/I3qgMPfs">speed</a> to a state of rest.
The <a href="/facts/International_System_of_Units/S7YLglNz">SI unit</a> of energy is the <a href="/facts/Joule/9ndq9jD2">joule</a>, while the <a href="/facts/English_Engineering_Units/RzM0JlQg">English unit</a> of energy is the <a href="/facts/Foot-pound/eYQsElep">foot-pound</a>.
In <a href="/facts/Special_relativity/vsFFc63E">relativistic mechanics</a>, 
 
 
 
 
 
 1
 2
 
 
 m
 
 v
 
 2
 
 
 
 
 {\textstyle {\frac {1}{2}}mv^{2}}
 
 is a good <a href="/facts/Approximation/LvYHsXzq">approximation</a> of kinetic energy only when v is much less than the <a href="/facts/Speed_of_light/sKSQwdNx">speed of light</a>.

Kinetic energy open-in-new

Kinetic energy