Answer: 2000 W.
- A 1500 W
- B 2500 W
- C 1000 W
- D 2000 W
Correct answer: D. 2000 W
Explanation: Mass rate = 10 kg/s. Power = mgh/t + (1/2)mv<sup>2</sup>/t = 10 × 10 × 15 + 0.5 × 10 × 100 = 1500 + 500 = 2000 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.