A pendulum is defined as any weight suspended from a pivot point in such a way that it is able to swing freely back and forth. Scientifically speaking, the weight, or mass, is referred to as "the bob". The bob is suspended on a rod, a string or a wire.
A pendulum can be as simple as a weight hanging from the end of the string, or as utilitarian as a swing. In this case, the person sitting on the swing is the bob, the chain is the wire and the structure to which the chain is affixed serves as the pivot point.
Pendulums have been used for a variety of different applications, including and most notably, the grandfather clock because of its function as a mechanical timekeeper.
The amount of time the pendulum takes to swing (or oscillate) right to left and back again is called the period.
A pendulum clock takes one second to move from one extreme to the other extreme; therefore, its period is two seconds.
There are four forces which act on a pendulum.
●Gravity (Fg) pulls the bob towards the earth.
●Tension (F⊤) acts along the wire towards the pivot point.
●The restoration force (Fr) acts to bring a body to its equilibrium position.
●The perpendicular gravitational force (F⟂) acts equally and opposite to F⊤.