Hello aspirant,

A simple pendulum is one which can be considered to be a point mass suspended from a string or rod of negligible mass. It is a resonant system with a single resonant frequency. Conical pendulum is an extension of simple pendulum in which the bob, instead of moving back and forth, moves at a constant speed in a circle in a horizontal plane. Thus together with the string the bob traces out a cone. Spherical pendulum and vertical pendulum are the special cases of conical pendulum.

A simple pendulum swings in a plane (2 dimensions) and maps out a sector of a circle. A conical pendulum swings in 3 dimensions and maps out the curved surface of a cone.

Hope, this information helps you.