Step Response of Undamped System

Q. Unit step response of second order system is shown in figure.


Transfer function of the system is

1. $\frac{5}{s^2+2s+5}$
2. $\frac{9.3}{s^2+2s+9.3}$
3. $\frac{2.7}{s^2+2s+2.7}$
4. $\frac{10}{s^2+2s+10}$

Q. The unit impulse response of a linear time invarient system is the unit step function $u\left(t\right)$. For $t>0$, the response of the system to an excitation $e^{-at}u\left(t\right),a>0$ will be

1. $a{e}^{-at}$
2. $\left(1/a\right)(1-e^{-at})$
3. $a(1-e^{-at})$
4. $1-e^{-at}$