The following diagram shows a pendulum at different positions (P and T are the extremes, R is the mean position). Which one of the following statements is true?

(a) The pendulum has minimum potential energy at positions P and T.
(b) The pendulum has minimum potential energy at positions Q and S.
(c) The pendulum has minimum potential energy at position R.
(d) The pendulum has same potential energy at all positions.

The gravitational potential energy (GPE) of a pendulum is determined by the formula GPE = mgh, where 'h' represents the height above a reference level. In a standard oscillating pendulum, the bob moves along an arc. The lowest point of this arc is the equilibrium position, typically labeled as the center point (R in this diagram). At this position, the height 'h' is at its minimum relative to the ground or the reference level, resulting in the minimum potential energy. Conversely, the extreme positions (P and T) represent the points of maximum height and zero speed, where potential energy is at its maximum. As the pendulum swings from the extremes toward the center, potential energy is converted into kinetic energy, which reaches its peak at the lowest point R.