6. Give the control-block diagram as shown in Fig. 3,Gp=s11,Gv=Gm=1, and Gc is a PI controller with gain -4 and time constant 20. The initial value of output is zero. (a. 20pts ) If the input ysp is a unit step function and D(s)=0, then determine y(t). (b. 10 pts) Determine the maximum value of the y(t). Figure 3: Control Block Diagram for Question 6