Answer:
C ) 33 s.
Explanation:
In simple harmonic motion damping of amplitude is logarithmic which is expressed as follows
[tex]A=A_0e^{-\frac{-b}{t}[/tex]
A/A₀ = .3 (given ) , b is damping constant and t is time which is 30 s here.
[tex].3 = e^\frac{-b}{t}[/tex]
ln .3 = -b / 30
1.2 = b / 30
b = 36 s 0r 33 s