The document discusses the Helmholtz resonator and how it is analogous to an LCR circuit. It explains that a Helmholtz resonator consists of a rigid enclosure connected to the external medium by a narrow opening. The gas in the opening acts as a mass and the pressure changes in the enclosure provide stiffness, similar to an LCR circuit. It also shows that the equations that describe forced oscillations in mechanics, an LCR circuit, and a Helmholtz resonator are analogous, with terms like mass, inductance, and damping coefficient having similar meanings across the three domains.

4. Compare the following equations