Answer: 1 J.
- A 0.5 J
- B 1 J
- C 2 J
- D 4 J
Correct answer: B. 1 J
Explanation: PE = (1/2)kx² = 0.5·200·(0.1)² = 1 J.
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.