Resonance in Music, Cars, and Radios

Resonance is a key feature of driven oscillators, and it depends strongly on damping. Damping is the process that reduces motion by removing energy from the system. When a system must resonate at one specific frequency, very light damping is needed. Piano strings and many other musical instruments are common examples of this...

Consider four pendulums tied to a string and suspended from a rigid support. Let the lengths of pendulums A and C be identical, while pendulums B and D have different lengths.

When pendulum A is displaced, it oscillates with a natural frequency, and the energy from pendulum A is transferred to the other pendulums, forcing them to oscillat...