A pendulum is an object that is suspended on a string and can swing freely from one side to another.The pendulum bob is displaced from its original position and then released with the string taut.The bob passes through the equilibrium position at maximum speed then slows down as its reaches the maximum height on the other side of the equilibrium position.The kinetic energy is maximum at the equilibrium position and zero at the maximum height because it slows to a halt before changing direction. The gravitational potential energy is a maximum at the maximum height and minimum at the equilibrium position.