Question

explain basic assumption in mechanics​

Answer 1

Explanation:

The fundamental assumption of statistical mechanics is that, over time, an isolated system in a given macrostate is equally likely to be found in any of it's microstates. Thus, our system of 2 atoms is most likely to be in a microstate where energy is split up 50/50.

Answer 2

Following is the basic postulate of statistical mechanics. "An isolated system in equilibrium is equally likely to be in any of its accessible states". For an isolated system, the energy of the system is conserved and independent of time.