Answer: Elastic potential energy.
- A Kinetic energy under most conditions encountered
- B Chemical energy as frequently observed in practice
- C Elastic potential energy
- D Thermal energy in many documented cases
Correct answer: C. Elastic potential energy
Explanation: A compressed spring stores elastic potential energy = (1/2)kx<sup>2.</sup>
As a pendulum swings, total mechanical energy (KE+PE) stays constant: at the highest points A and C, all energy is potential (zero speed); at the lowest point B, all of that energy has converted into kinetic energy (maximum speed).
Concept context
Work-energy theorem, potential energy, conservation of energy, collisions.