Editing Coupling (physics) (section)

=== Coupled harmonic oscillator ===
[[File:Coupled.svg|thumb|Coupled pendulums connected by a spring]]
If two [[Waves (physics)|waves]] are able to transmit [[energy]] to each other, then these waves are said to be "coupled." This normally occurs when the waves share a common component. An example of this is two pendulums connected by a [[Spring (device)|spring]]. If the pendulums are identical, then their equations of motion are given by
<math display="block">m\ddot{x} = -mg\frac{x}{l_1} - k(x-y)</math>
<math display="block">m\ddot{y} = -mg \frac{y}{l_2} + k(x-y)</math>

These equations represent the [[simple harmonic motion]] of the pendulum with an added coupling factor of the spring.<ref name=":0">{{Cite book|title=The Physics of Vibrations and Waves | edition = Fourth | last=Pain|first=H.J.| publisher=Wiley | year=1993| isbn=0-471-93742-8|location=West Sussex, England}}</ref> This behavior is also seen in certain molecules (such as [[Carbon dioxide|CO<sub>2</sub>]] and H<sub>2</sub>O), wherein two of the atoms will vibrate around a central one in a similar manner.<ref name=":0" />