Answer: 100 W.
- A 10 W
- B 100 W
- C 1000 W
- D 10000 W
Correct answer: B. 100 W
Explanation: P = W/t = 1000/10 = 100 W.
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.