Comparing Eq. 13 and Eq. 9, we understand that the difference between the total energy change in Newtonian mechanics and thermodynamics theories is the presence of heat in thermodynamics. We know that the transferred heat that performs expansion work and therefore converts to the potential energy of the upper system is originally rooted in the entropic energy of the surrounding. This heat transfer to the system causes an increase in the system's entropy which in turn leads to the return of the heat to the surrounding as the system expands and loses its energy. In fact, it is the increase in the stochastic fluctuations of microscopic degrees of freedom that lead to an increase in the heat and when these motions reach the system's boundaries, the heat transmits to the surrounding. Also, for the system to perform useful work, some of its energy is lost as dissipated work owing to the very random Brownian motions of particles. On the basis of this information, we comprehend that to extract equivalent work in thermodynamics to Newtonian mechanics in a real system, the required amount of heat should be larger than the corresponding applied external energy in Newtonian mechanics. To understand this further we need to discuss Helmholtz free energy. If we subtract the reciprocal heat from total energy, the Helmholtz free energy change of the system will return as follows: