Resonance
A big response when a driving force matches an object's natural frequency. Damping limits how big it gets.
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Analogy
Pushing a swing at the right moment each cycle makes it go higher.
Example
Natural period 3 s.Push every 3 s: height grows.Push every 2 s: little effect.
In practice
Soldiers break step on bridges so their marching does not match the bridge's natural frequency.
Practice
Flashcards
- What happens at resonance?The amplitude grows large because the driving frequency matches the natural frequency.
Questions people ask
Why can an opera singer break a glass?
Every glass has a natural frequency. If a singer sustains a loud note at that frequency, the glass vibrates with growing amplitude. Eventually the glass flexes beyond its limit and shatters. The sound must be loud enough and exactly on the matching pitch for this to happen.
What is damping?
Damping is energy loss that makes oscillations die away, usually through friction or air drag. A car's shock absorbers are damped on purpose so the car stops bouncing quickly. Heavy damping lowers and widens the resonance peak, which protects structures from large vibrations.