Question

The transfer function of a system is G(s) = 100/(s+1) (s+100). For a unit step input to the system the approximate settling time for 2% criterion is:

(a) 100 sec

(b) 4 sec

(c) 1 sec

(d) 0.01 sec

I got this question during an online exam.

This interesting question is from Time Response of Second Order Systems topic in section Time Response Analysis, Design Specifications and Performance Indices of Control Systems

Answer 1

Right option is (b) 4 sec

The explanation is: Comparing the equation with the characteristic equation and then finding the value of G and w and calculating the value of settling time as 4 sec from 4/Gw.