# Vibratory Motion

Vibratory motion is one of the three basic types of motions. The three basic types of motions are translator motion which is along a straight line or along a given path, rotatory motion which is around a centre point in concentric circles and vibratory motion which is about a fixed point where an object moves to and fro.

Vibratory MotionWhen an object is displaced from its fixed position and made to move to and fro periodically, it is known as vibratory motion. A vibratory motion happens when a particle is vibrated. Vibratory motion is also called as oscillatory motion.Types of Vibratory MotionFree Vibratory motion and Forced Vibratory motionWhen an object is made to vibrate with an initial application of force and then allowed to vibrate freely, a free vibration occurs. When a child is seated on a swing and the swing is let go the swing makes to and fro motions freely.

The frequency of these motions reduces gradually and finally come to a zero when the swing comes to a halt. This is a free vibratory motion.Forced vibration is when a force is applied to an object at regular intervals which causes a to and fro motion in the object. Examples for this type of vibration are transportation vibration caused by truck engine or bad roads, or building vibration during an earthquake. In forced vibration the frequency of the to and fro motion of the object along a fixed point does not reduce gradually, instead the frequency is dependent upon the frequency of the force applied.

A simple Pendulum is a classic example of Vibratory motionA simple pendulum consists of a round object of mass m hanging from a cord of length L and is fixed at a pivot point P. When the pendulum is displaced to an angle and released, the pendulum swings back and forth with periodic motion against the pivot point P. This is called a vibratory motion.simple pendulumVibratory motion of a Simple Pendulum 1Conclusion to Vibratory MotionThus vibratory motion is periodic motion of particles about a fixed point. Vibratory motions can be free vibratory motions or forced vibratory motions. Real life application of vibratory motion can be seen in musical instruments especially the string instruments, speakers, in light bulbs and swings.