Answer: π/6 rad.
- A π/6 rad
- B 10 rad
- C 5 rad
- D π/3 rad
Correct answer: A. π/6 rad
Explanation: In x = A sin(ωt + φ), the initial phase (phase at t=0) is φ = π/6 rad = 30°.
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.