Question

Can anybody explain me the physical interpretation of Second order system rather than it's mathematical expression

Answer 1

check this out.

http://www.facstaff.bucknell.edu/mastascu/econtrolhtml/SysDyn/SysDyn2.html

Answer 2

lets take up the example of the pendulum.
The motion of a pendulum is the second order behavior.
Here the gravity tries to bring the metal bob to the lowest position, but due the kinetic energy it moves to the other side. But this time the bob does not go to the extreme position but to a position converging in the direction of center position. This happened due to the drag offered by the air. This air drag accounts for the damping of the motion or the damping factor.

Now imagine this pendulum in motion submerged in water. Here the drag would be mode i.e. more damping factor. The bob will quickly stabilize to the center position.

Now if the same were happening submerged in jelly or glycerin or honey.