Answer to Question #71707 in Mechanics | Relativity for saliha yaqoob
Why does second law of thermodynamics require different temperature for work done?
Let's explain on the following example. Work in thermal engines is performed by expanding the working body. To make the work of the machine continuous, the working body must be returned to its original state. To this end, it must be compressed, having spent work. If the compression is carried out at the same temperature as the expansion, then it will be necessary to expend all the work received during the expansion, and the efficiency of this engine will be zero. In order for the compression work to be less than the expansion work, it is necessary to compress at a lower temperature.