Vibration

in mechanics, a regular reciprocal motion of a body, as, for example, a pendulum, which, being freely suspended, swings or vibrates from side to side. Mechanical authors, instead of vibration, often use the term escillation, especially when speaking of a body that thus swings by means of its own gravity or weight. The vibrations of the same pendulum are all isochronal; that is, they are performed in an equal time, at least, in the same latitude; for in lower latitudes they are found to be. slower than in. higher ones. See PENDULUM. In our latitude, a pendulum 39; inches long vibrates seconds, making 60 vibrations in a minute. The vibrations of a longer pendulum take up more time than those of a shorter one, and that in the sub-duplicate ratio of the lengths), or the ratio of the square roots of the lengths, Thus, if one pendulum be 40 inches long, and. another only 10 inches long, the former will be double the time of the latter in performing a vibration; for./ 40: 4/103: of 4: 4/1, that is, as two.to One. And. because the number of vibrations, made in any given time, jis reciprocally as the. duration of one vibration, therefore the number of such vibrations is in the reciprocal subduplicate ratio. of the lengths of the pendulums, - Vibrations of a stretched chord, or string, arise from its elasticity; which. power being in this case similar to gravity, as acting unie: formly, the vibrations of a chord follow the same laws. as those of pendulums. Consequently the vibrations of ‘the same chord, equally stretched, though they be of unequal lengths, are isochronal, or are performed in, equal times; and the squares of the times of. vibration are to one another inversely as their tensions, or powers by which they are stretch= ed. The vibrations of a spring, too, are proportional to the powers by which it is bent.. These follow the same laws as. those of the: chord and pendulum; and consequently are isochronal, which is the foundation of springs. watches. See Cuorp and Music.