Answer: Directly proportional to displacement and directed toward equilibrium.
- A Directly proportional to displacement and directed toward equilibrium
- B Constant in magnitude regardless of displacement, like kinetic friction
- C Directly proportional to velocity, as in viscous damping
- D Inversely proportional to displacement, growing without bound near equilibrium
Correct answer: A. Directly proportional to displacement and directed toward equilibrium
Explanation: SHM is defined by F = -kx. The force is proportional to displacement and always points back toward equilibrium (hence the negative sign).
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.