Answer: 1 kWh.
- A 0.1 kWh
- B 1 kWh
- C 5 kWh
- D 10 kWh
Correct answer: B. 1 kWh
Explanation: E = P x t = 0.2 kW x 5 h = 1 kWh.
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.