Answer: 2 m/s.
- A 1 m/s
- B 2 m/s
- C 4 m/s
- D 10 m/s
Correct answer: B. 2 m/s
Explanation: Spring PE = (1/2)kx<sup>2</sup> = (1/2)(100)(0.04) = 2 J = KE = (1/2)mv<sup>2.</sup> v = sqrt(4) = 2 m/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.