State what is meant by resonance and provide some examples where it is crucial.

Resonance is where a system is forced to oscillate at a frequency close or at its natural frequency. The result of the forced oscillation produces a maximum energy transfer and, therefore, a large increase in amplitude of the oscillating body. Examples where the forced oscillation of a body near its natural frequency is crucial could be demonstrated with an instrument like the guitar. With this case the diameter and material of the string will determine the sound wave produced that will resonate in the cavity of the guitar. Therefore, producing a particular sound wave desired by the musician.