Pendulum bob
Pendulum Pen"du*lum, n.; pl. {Pendulums}. [NL., fr. L. pendulus hanging, swinging. See {Pendulous}.] A body so suspended from a fixed point as to swing freely to and fro by the alternate action of gravity and momentum. It is used to regulate the movements of clockwork and other machinery. [1913 Webster]

Note: The time of oscillation of a pendulum is independent of the arc of vibration, provided this arc be small. [1913 Webster]

{Ballistic pendulum}. See under {Ballistic}.

{Compensation pendulum}, a clock pendulum in which the effect of changes of temperature of the length of the rod is so counteracted, usually by the opposite expansion of differene metals, that the distance of the center of oscillation from the center of suspension remains invariable; as, the mercurial compensation pendulum, in which the expansion of the rod is compensated by the opposite expansion of mercury in a jar constituting the bob; the gridiron pendulum, in which compensation is effected by the opposite expansion of sets of rodsof different metals.

{Compound pendulum}, an ordinary pendulum; -- so called, as being made up of different parts, and contrasted with {simple pendulum}.

{Conical pendulum} or {Revolving pendulum}, a weight connected by a rod with a fixed point; and revolving in a horizontal cyrcle about the vertical from that point.

{Pendulum bob}, the weight at the lower end of a pendulum.

{Pendulum level}, a plumb level. See under {Level}.

{Pendulum wheel}, the balance of a watch.

{Simple pendulum} or {Theoretical pendulum}, an imaginary pendulum having no dimensions except length, and no weight except at the center of oscillation; in other words, a material point suspended by an ideal line. [1913 Webster]

The Collaborative International Dictionary of English. 2000.

### Look at other dictionaries:

• Pendulum — Pen du*lum, n.; pl. {Pendulums}. [NL., fr. L. pendulus hanging, swinging. See {Pendulous}.] A body so suspended from a fixed point as to swing freely to and fro by the alternate action of gravity and momentum. It is used to regulate the movements …   The Collaborative International Dictionary of English

• Pendulum level — Pendulum Pen du*lum, n.; pl. {Pendulums}. [NL., fr. L. pendulus hanging, swinging. See {Pendulous}.] A body so suspended from a fixed point as to swing freely to and fro by the alternate action of gravity and momentum. It is used to regulate the… …   The Collaborative International Dictionary of English

• Pendulum wheel — Pendulum Pen du*lum, n.; pl. {Pendulums}. [NL., fr. L. pendulus hanging, swinging. See {Pendulous}.] A body so suspended from a fixed point as to swing freely to and fro by the alternate action of gravity and momentum. It is used to regulate the… …   The Collaborative International Dictionary of English

• Bob — may refer to:* A diminutive of Robert * Bob (physics), the weight at the end of a pendulum * BOB (band), a UK indie pop band * Bob (song), a song by Weird Al Yankovic from Poodle Hat * Bob , a song by the Red Hot Chili Peppers from the album One… …   Wikipedia

• Bob (physics) — A bob is the weight on the end of a pendulum.The use of a weight concentrated in a small, compact object enables the centre of gravity to be positioned close to the physical end of the pendulum, which minimises the length of pendulum required for …   Wikipedia

• Pendulum clock — A pendulum clock is a clock that uses a pendulum, a swinging weight, as its timekeeping element. From its invention in 1656 by Christiaan Huygens until the 1930s, the pendulum clock was the world s most accurate timekeeper, accounting for its… …   Wikipedia

• pendulum watch — noun (18th century) a watch with a balance wheel having a fake pendulum attached to it • Hypernyms: ↑watch, ↑ticker * * * noun : a late 18th century watch with a mock pendulum attached to a concealed balance wheel and showing through a curved… …   Useful english dictionary

• pendulum watch — (formerly) a watch having a balance wheel, esp. a balance wheel bearing a fake pendulum bob oscillating behind a window in the dial. [1655 65] * * * …   Universalium

• Bob — (b[o^]b), n. [An onomatopoetic word, expressing quick, jerky motion; OE. bob bunch, bobben to strike, mock, deceive. Cf. Prov. Eng. bob, n., a ball, an engine beam, bunch, blast, trick, taunt, scoff; as, a v., to dance, to courtesy, to disappoint …   The Collaborative International Dictionary of English