Question

A simple pendulum in which the bob swings in a horizontal circle is called:
(A) Compound pendulum
(B) Horizontal pendulum
(C) Conical pendulum
(D) Gallitzin pendulum

Answer 1

A pendulum is made up of a weight (or bob) hung from a pivot at the end of a string or rod. It has a similar construction to a regular pendulum, but instead of swinging back and forth, the bob of a pendulum swings in a circle at a constant speed, with the string (or rod) sketching out a cone.

Complete answer:
A simple pendulum in which the bob swings in a horizontal circle is called a conical pendulum.
A conical pendulum is made up of a weight (or bob) hung from a pivot at the end of a string or rod. It has a similar construction to a regular pendulum, but instead of swinging back and forth, the bob of a conical pendulum swings in a circle at a constant speed, with the string (or rod) sketching out a cone.
A simple pendulum, on the other hand, swings back and forth in a vertical plane. The bob swings up at the extremities of the swing and dips down in the midst of the arc. The bob on the conical pendulum remains at the same height while tracing a horizontal circular route.
A compound pendulum is a body that is capable of oscillating around a horizontal axis. The radius of gyration, the mass of the pendulum, and the acceleration due to gravity all influence the frequency of a compound pendulum.
Around 1660, English physicist Robert Hooke investigated the conical pendulum as a model for planet orbital motion. In his book Horologium Oscillatorium, published in 1673, Dutch scientist Christiaan Huygens estimated its time using his novel idea of centrifugal force. It was later employed to keep time in a few mechanical clocks and other clockwork timing devices.
Conical pendulums were used as the timekeeping element in a few clockwork timing machines in the 1800s where a smooth motion was required, rather than the jerky motion offered by regular pendulums. Two examples are the motors that move lighthouse lenses to sweep their beams across the sea and the location drives of equatorial mount telescopes, which allow the telescope to smoothly follow a star across the sky as the Earth rotates.
Hence, the correct option is (C) Conical pendulum.

Note:
The flyball governor (centrifugal governor) created by James Watt in 1788, which governed the speed of steam engines during the Steam Age in the 1800s, was one of the most important uses of the conical pendulum. Tetherball is a playground game in which a ball is tethered to a pole by a string that acts as a conical pendulum. As the cord wraps around the pole, the pendulum gets shorter. Conical pendulums are used in some amusement park rides.