Vibration is the periodic back and forth motion of the particles of an elastic body or medium. It usually arises when a physical system is displaced from its equilibrium condition and allowed to respond to the forces that tend to restore equilibrium.
The motion may be periodic, as in the motion of a struck pendulum. Or the motion can be completely random, such as the movement of a tire rolling along a rough road.
As defined in physics, vibration is the oscillating, reciprocating, or other periodic motion of a rigid or elastic body or medium forced from a position or state of equilibrium.
In some cases, vibrations can be advantageous—as with the reed in a woodwind musical instrument or in a vibratory parts hopper that dispenses discrete items from a funneled drum. But in many cases vibration is destructive. It can waste energy and create imbalances, friction, and failure in mechanical devices.
Vibration and sound studies are closely associated. Sound waves are generated by vibrating structures. These pressure waves also induce the vibration of structures or systems. Attempts to reduce unwanted noise are generally related to issues of vibration.
