The displacement of a damped harmonic oscillator is given by

PHYSICS · Single correct · A Level · Physics · Further mechanics and thermal physics · Further mechanics and thermal physics

Problem

x(t) = e^{-0.1t} \cdot \cos(10\pi t + \phi)

. Here

t

is in seconds. The time taken for its amplitude of vibration to drop to half of its initial value is close to: (1) 4s (2) 7s (3) 13s (4) 27s