(a) The concept of duality can be extended to nonelectric physical systems by means of analogs. For example, the mechanical system characteristics can be investigated by means of an equivalent electrical network. Consider Newton's second law, Hooke's law as applied to springs, and viscous friction law, and find the force-current analog as well as the force- voltage analog by identifying the analogous mathematical relations.
(b) Consider the analogy between electrical and hydraulic systems given in Table 1.5.2. Obtain the mass balance equation by equating the rate of change of fluid volume to the net difference between input and output flow. Identify this equation with that of an RC circuit excited by a current source i(t) = I.
