Differentiate between damped and undamped oscillations

In which  case the amplitude of oscillations becomes too large?

The amplitude of a damped oscillator becomes ${\left(\frac{1}{3}\right)}^{\mathrm{rd}}$ in $2 \mathrm{s}$. If its amplitude after $6 \mathrm{s}$ is $\frac{1}{n}$ times the original amplitude, the value of $n$ is

The suspension system of a $2400 \mathrm{kg}$ automobile sags $10 \mathrm{cm}$ when the chassis is placed on it. Also, the oscillation amplitude decreases by $50\%$ per cycle. Estimate the values of,

(a) the spring constant $k$, and

(b) the damping constant $b$ for the spring and shock absorber system of one wheel, assuming each wheel supports $600 \mathrm{kg}$.

The amplitude of a damped oscillator decreases to $0.9$ times its original magnitude in $5 \mathrm{s}$. In another $10 \mathrm{s}$ it will decrease to $\alpha$- times its original magnitude, where $\mathrm{\alpha }$ equals$:$