Answer: 225000 J.
- A 75000 J
- B 150000 J
- C 225000 J
- D 450000 J
Correct answer: C. 225000 J
Explanation: W = Delta KE = (1/2)(500)(900) - 0 = 225000 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.