Consider the closed-loop system shown in Figure P11.6, where the transfer function of the process is that of a second-order system, i.e.
$$
G_p(s)=\frac{k_p}{\tau^2 s^2+2 \zeta \tau s+1}
$$
If the controller is a P controller $\left(G_c(s)=k_c\right)$
(a) determine the closed-loop transfer function
(b) determine the offset to a unit step change of the set point.