Answer:
C ) 33 s.
Step-by-step explanation:
In simple harmonic motion damping of amplitude is logarithmic which is expressed as follows
![A=A_0e^{-(-b)/(t)](https://img.qammunity.org/2020/formulas/physics/college/izxvdeiptwdwui1h2t4zicpl2g1cl4wsjm.png)
A/A₀ = .3 (given ) , b is damping constant and t is time which is 30 s here.
![.3 = e^(-b)/(t)](https://img.qammunity.org/2020/formulas/physics/college/a054syvdtdnl6tpvbq6h7kcin8h7ow2zeo.png)
ln .3 = -b / 30
1.2 = b / 30
b = 36 s 0r 33 s