Answer: 1.99 s.
- A 1.99 s
- B 2.43 s
- C 1.57 s
- D 2.81 s
Correct answer: A. 1.99 s
Explanation: T = 2π√(I/mgd) = 2π√((mL<sup>2</sup>/3)/(mg·L/2)) = 2π√(2L/3g) = 2π√(2×1.5/30) = 2π√0.1 = 1.99 s.
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.