Question

how does a simple pendulum work

Answer 1

A pendulum works by converting energy back and forth, a bit like a rollercoaster ride. ... As it accelerates down toward its lowest point (its midpoint, nearest the ground), this potential energy is converted into kinetic energy (energy of movement) and then, as the bob climbs up again, back to potential energy.

Answer 2

A pendulum is a weight suspended from a pivot so that it can swing freely. When apendulum is displaced sideways from its resting, equilibrium position, it is subject to a restoring force due to gravity that will accelerate it back toward the equilibrium position.