A second order system has a transfer function given by $$\mathrm G\left(\mathrm s\right)\;=\;\frac{25}{\mathrm s^2\;+\;8\mathrm s\;+\;25}$$ .If the system, initially at rest is subjected to a unit step input at t = 0, the second peak in response will occur at

The steady state error of a stable 'type 0' unity feedback system for a unit step function is

A critically damped, continuous-time, second order system, when sampled, will have ( in Z domain)