What is simple pandulem?

A simple pendulum consists of a mass (or bob) attached to a string or rod of fixed length that swings back and forth under the influence of gravity. It exhibits periodic motion, with the time it takes to complete one full swing (the period) depending on the length of the pendulum and the acceleration due to gravity. The motion can be described by simple harmonic motion principles when the angle of displacement is small. Simple pendulums are often used in physics demonstrations to illustrate concepts of oscillation and gravitational effects.