Vi*bra"tion (?), n. [L. vibratio: cf.
F. vibration.] 1. The act of vibrating, or the
state of being vibrated, or in vibratory motion; quick motion to and fro;
oscillation, as of a pendulum or musical string.
As a harper lays his open palm
Upon his harp, to deaden its vibrations.
Longfellow.
2. (Physics) A limited reciprocating motion
of a particle of an elastic body or medium in alternately opposite
directions from its position of equilibrium, when that equilibrium has been
disturbed, as when a stretched cord or other body produces musical notes,
or particles of air transmit sounds to the ear. The path of the particle
may be in a straight line, in a circular arc, or in any curve
whatever.
☞ Vibration and oscillation are both used, in
mechanics, of the swinging, or rising and falling, motion of a suspended or
balanced body; the latter term more appropriately, as signifying such
motion produced by gravity, and of any degree of slowness, while the former
applies especially to the quick, short motion to and fro which results from
elasticity, or the action of molecular forces among the particles of a body
when disturbed from their position of rest, as in a spring.
Amplitude of vibration, the maximum displacement
of a vibrating particle or body from its position of rest. --
Phase of vibration, any part of the path described by
a particle or body in making a complete vibration, in distinction from
other parts, as while moving from one extreme to the other, or on one side
of the line of rest, in distinction from the opposite. Two particles are
said to be in the same phase when they are moving in the same
direction and with the same velocity, or in corresponding parts of their
paths.