In a pendulum, what happens to the potential and kinetic energy as it swings?

• A. Potential energy is highest at the lowest point
• B. Kinetic energy remains constant throughout the swing
• C. The energies continually transform back and forth
• D. Energy is lost as heat at each swing

Answer: (C)

As a pendulum swings, the motion demonstrates the conservation of mechanical energy, where potential energy and kinetic energy continuously transform into one another. When the pendulum is at its highest points (the extremes of the swing), its potential energy is maximized because it has the highest altitude, while its kinetic energy is minimal since it momentarily comes to a stop before reversing direction. As it swings down towards the lowest point in the arc, potential energy decreases while kinetic energy increases, reaching its maximum at the lowest point where the pendulum is moving fastest.

This transformation is cyclical; repeating as the pendulum swings back and forth. The energy continually changes forms between potential and kinetic energy throughout the motion, illustrating the principle of conservation of energy within the system. Therefore, the correct response highlights the dynamic nature of energy in the pendulum's movement.