Ease of Excitation at Resonance
It is easy to get an object to vibrate at its resonant frequencies, hard
at other frequencies. A child's playground swing is an example of a pendulum, a resonant system with only one resonant frequency. With a tiny push on the swing each time it comes back to you, you can continue to build up the amplitude of swing. If you try to force it to swing at twice that frequency, you will find it very difficult, and might even lose teeth in the process!
|Swinging a child in a playground swing is an easy job because you are helped by its natural frequency.||But can you swing it at some other frequency?||Index|