Main Principles of Classical Mechanics In classical mechanics, a system can be described by a number of dynamic variables. The goal is to be able to calculate the exact values of these variables at any given time and determine how these values evolve as a function of time t. Once the position x(t) of a particle within a one-dimensional system is known, a series of other variables such as the velocity v(t), acceleration a(t), momentum p(t), potential energy V, and kinetic energy K can be calculated. Newton's Law is the basis of classical mechanics: F = ma or F = dp/dt where F is the force acting on the particle and m is the mass of the particle.