Answer: Work / time.
- A Work x time
- B Work / time
- C Force x time
- D Energy x time
Correct answer: B. Work / time
Explanation: Power = Work done / time taken = W/t. SI unit is Watt (W) = J/s.
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.