Answer: Equilibrium position.
- A Equilibrium position
- B Extreme positions
- C Halfway between equilibrium and extreme
- D Any position
Correct answer: A. Equilibrium position
Explanation: At equilibrium (x=0), all energy is kinetic: KE_max = (1/2)kA². At extremes, KE = 0 and PE = (1/2)kA².
In SHM, displacement and velocity are 90° out of phase (v is maximum when x=0, and zero when x is extreme), while acceleration is always exactly opposite in sign to displacement, consistent with a = −ω²x.
Concept context
Simple harmonic motion, spring-mass, pendulum, energy in SHM, and resonance.