Definition:Pendulum

Definition
A pendulum is an ideal body consisting of two parts:
 * $(1): \quad$ a rod attached at one end to a pivot
 * $(2): \quad$ a point mass at the other end of the rod.


 * Pendulum.png

The pendulum is embedded in a gravitational field.

Bob
Hence the bob is free to swing under the effects of the gravitational field.

Also defined as
Some treatments specify that, instead of a rod, the bob is suspended from the pivot by an ideal thread.

The treatment is similar to that of the rod, but the behaviour of the pendulum when the bob rises above the pivot is different.

In all cases, the statement of the problem should define which arrangement is in effect.

Also known as
A pendulum as defined here is often referred to as a simple pendulum, so as to distinguish it from a compound pendulum.