Comment on ‘Work done by sliding friction on an incline’

When an object slides across a surface, macroscopic mechanics cannot predict how the total thermal energy that is generated gets partitioned between the object and the surface. However, thermodynamics defines work as a quantity of energy gained (or lost) by one system with an equal amount lost (or gained) by another system (called the surroundings of the first system) as a result of a force acting between them. Using this definition, the work that the object (taken to be the system) performs on the surface (taken to be the surroundings) due to sliding friction cannot be determined solely from knowledge of the initial and final bulk mechanical energies involved.