The average kinetic energy of the particles in a substance refers to the mean value of the kinetic energies of all the individual particles within that substance. In the case of the substance made up of 1,000 particles, the average kinetic energy is calculated by summing the kinetic energies of all 1,000 particles and then dividing by the total number of particles (which in this case is 1,000).
This average value provides a single representative measure that characterizes the overall kinetic energy of the particles in the substance, regardless of the variations in the kinetic energies of the individual particles. Therefore, while some particles may have higher kinetic energy and some lower, the average kinetic energy gives an idea of the general state of motion of the particles as it relates to temperature.
In summary, the average kinetic energy is an important concept that helps to define the temperature of a substance, and it encapsulates the collective motion of all the particles rather than focusing on any individual particle.