The simplest form of periodic motion is represented by an object oscillating on the end of a uniform coil spring. Many other types of vibrational motion closely resemble this system. We assume that the mass of the spring can be ignored, and the object of mass slides without friction on the horizontal surface. Equilibrium position: where the net force acting on the mass is 0. We set this position as the origin of `x` axis. displacement: The distance `x` of the mass from the equilibrium point at any moment. Amplitude: The maximum displacement form the equilibrium point. Cycle: One cycle refers to the complete to-and-fro motion from same initial point back to the same point. Period: The period (`T`), is defined as the time required to complete one cycel. Frequency: The frequency (`f`), if the number of complete cycles per second.