Reaching equilibrium: the role of dissipation in analogous systems, within a thermodynamic-like perspective

Isomorphic problems play an acknowledged pedagogical role in the physicsteaching/learning process. In this context, we describe a unified approachto a wide class of physical systems formally analogous to the well-known‘two-capacitor system’. The proposed learning path, specifically addressed touniversity students, provides the opportunity to introduce a unitary graphicalrepresentation that is very suitable to describe the system energy evolution, aswell as allowing the highlighting of the mutually exclusive roles of dissipationand reversibility when the system approaches its equilibrium conditions (where‘equilibrium’ must be interpreted in its most general meaning, either as ‘staticequilibrium’ or as ‘steady state’). Moreover, a new quantitative modeling isintroduced for two representative systems, in order to show that the energy‘missed’ during the equilibrium achievement is just equal to the negative workan external agent should make to let the system reach its final state quasistaticallyand reversibly.