Question

A pendulum is oscillating on either side of its rest position. The correct statement is:

• A. It has only the kinetic energy.
• B. It has the maximum kinetic energy at its extreme position.
• C. It has the maximum potential energy at its rest position.
• D. The sum of its kinetic and potential energies remains constant throughout the motion.

Answer 1

The correct option is D The sum of its kinetic and potential energies remains constant throughout the motion.

As energy is conserved the sum of its kinetic and potential energies remains constant throughout the motion.In this case, as there are only two forms of energies that are kinetic and potential energies for total energy, only these two energies comes into the count.It will have maximum $K.E$ at equilibrium position as it has maximum velocity at that point where as maximum $P.E$ at extreme positions as the distance from equilibrium is maximum.