What is the definition of work in thermodynamics?

Answer 1

In thermodynamics, work is all energy transferred between systems by any mechanism other than a temperature gradient; energy transferred strictly as a result of two systems at different temperatures coming into contact is defined as "heat" in thermodynamics. Thermodynamic work encompasses mechanical work as well as many other types of work, such as electrical or chemical. This is broader than the definition usually presented in physics (kinematics to be exact) where work is defined only as:

W = F·d

where

W is work

F is force

d is distance

Additional Answer

Work (W) is energy in transit from one form to another -in other words, work is done whenever one form of energy is converted into another. For example, an electric motor does work when it converts electrical energy into mechanical energy. Heat (Q) describes energy in transit from a warmer body to a cooler body. Work and heat are closely related: the difference between work and heat transfer is equal to the change in the internal energy (U) of a body, i.e.:

W - Q = (Ufinal - Uinitial)