Thermodynamics

The state of a system is defined by ascribing values to a sufficient number of variables. In mechanics, the state of a body is specified by means of a few measurable quantities, such as the position of centre of mass, its velocity and acceleration etc. In thermodynamics, however we disregard these mechanical coordinates and instead consider the interior of the system, find out directly or indirectly by experiments same measurable quantities upon which the internal state of the system for all thermodynamic purposes, the state of a system can be represented by specifying its pressure p, volume V and the temperature T provided the system is in equilibrium.