Resonance

In physics, resonance is the tendency of a system to vibrate with increasing amplitudes at some frequencies of excitation. These are known as the system's resonant frequencies (or resonance frequencies).Tongue, Benson, Principles of Vibration, Oxford University Pres, 2001,  The resonator may have a fundamental frequency, and any number of harmonics.

An example of useful effect of resonant frequency is a guitar string which makes a characteristic noise when it is touched. The noise depends on how thick or slack the string is.

Another example can be seen in a playground swing. There is one specific rate at which you must push away a person on a swing to cause the swing to go high. This rate is the resonant frequency.

In earthquake engineering, on contrary, any possibility of a resonance is detrimental for the building structure.

The Kirkwood gap and other connections among orbits are caused by orbital resonance.

Related pages
 Resonator
 Seismic damper
 Vibration control
 Vibration isolation

References

Category:Physics
Category:Mechanical vibrations
Category:Earthquake engineering
Category:Waves
Category:Oscillation