Editing Acceleration (section)

===Special relativity===
{{main|Special relativity|Acceleration (special relativity)}}
The special theory of relativity describes the behaviour of objects travelling relative to other objects at speeds approaching that of light in vacuum. [[Newtonian mechanics]] is exactly revealed to be an approximation to reality, valid to great accuracy at lower speeds. As the relevant speeds increase toward the speed of light, acceleration no longer follows classical equations.

As speeds approach that of light, the acceleration produced by a given force decreases, becoming [[infinitesimally]] small as light speed is approached; an object with mass can approach this speed [[asymptotically]], but never reach it.