Abstract
According to the second law of thermodynamics every spontaneous change, or process, is associated with an increase in entropy. Although the probabilistic distributions of particles and energy give the possible direction of a process, its occurrence is enabled by the motional energy of the particles. Even particles, however, are subjected to constraints of motion that slow down the attainment of some possible changes and thereby reduce their probability of occurrence, especially if alternative pathways to increase entropy are possible and can be accessed faster. Kinetic restraints are therefore key determinants of which processes are activated among the different possible ones.
Keywords: Average kinetic energy, Constraints of motion, Energy redistribution, Energy spreading, Particles collisions, Particle motion, Zeroth law.