Frequency Response of Second Order System

Q. The frequency response
$G\left(s\right)=1/\left[s\right(s+1\left)\right(s+2\left)\right]$ plotted in the complex $G\left(j\omega \right)$ plane $(for0<\omega <\infty )$ is

1. 
2. 
3. 
4. 

Q. The $3-dB$ bandwidth of a typical second-order system with the transfer function
$\frac{C\left(s\right)}{R\left(s\right)}=\frac{{\omega }_n^2}{s^2+2\xi {\omega }_{n}s+{\omega }^{2}n},$ is given by

1. ${\omega }_n\sqrt{1-2{\xi }^2}$
2. ${\omega }_n\sqrt{(1-{\xi }^2)+\sqrt{{\xi }^4-{\xi }^2+1}}$
3. ${\omega }_n\sqrt{(1-2{\xi }^2)+\sqrt{4{\xi }^4-4{\xi }^2+2}}$
4. ${\omega }_n\sqrt{(1-2{\xi }^2)-\sqrt{4{\xi }^4-4{\xi }^2+2}}$

Q.

A car moving with a velocity of $36km{h}^{-1}$ crosses a siren of frequency $500Hz$. The apparent frequency of siren after passing it will be

1. $520Hz$

2. $485Hz$

3. $540Hz$

4. $460Hz$