In thermodynamics, work done by or on a system arises from quasi-static volume change against an external pressure, formalized as W = PΔV, derived from the classical mechanics definition of work (force times distance) applied to a piston where force equals pressure times area. This connects to the first law of thermodynamics, ΔU = Q − W, which relates a system's change in internal energy to heat added and work done by the system, distinguishing macrostate variables (pressure, volume, temperature) from the underlying microstate behavior of particles. The concept belongs to the domain of thermodynamics and statistical mechanics, bridging macroscopic state descriptions with microscopic kinetic energy transfer.
In thermodynamics, work done by or on a system arises from quasi-static volume change against an external pressure, formalized as W = PΔV, derived from the classical mechanics definition of work (for…