Why does this transfer function has a second zero

1. What is the effect of zeros in the transfer function of a 2nd order system?
2. What does a zero do in a transfer function?
3. Why are there more poles than zeros?
4. What happens when a zero is added to the open loop transfer function?

What is the effect of zeros in the transfer function of a 2nd order system?

The standard second-order system has no zeros in the transfer function. If the system is modified to include a zero in it, the overshoot and settling time are greatly affected by the location of that zero.

What does a zero do in a transfer function?

Poles and Zeros of a transfer function are the frequencies for which the value of the denominator and numerator of transfer function becomes zero respectively. The values of the poles and the zeros of a system determine whether the system is stable, and how well the system performs.

Why are there more poles than zeros?

When a system has more poles than finite zeros (i.e. the transfer function of the system is strictly proper) then the system is causal. If the transfer function of a system has relative degree equal to 0 then the system is causal and there is also instantaneous transfer between input and output.

What happens when a zero is added to the open loop transfer function?

If we include a zero in the open loop transfer function, then some of root locus branches will move towards left half of 's' plane. So, it will increase the control system stability. In this case, the damping ratio δ increases.