1. Consider a DC motor control system using only the Proportional (P) controller and its block diagram is as shown below in Figure 1. Vi(s) P Controller Kp 2 1 S Motor 1 Vo(s) Figure 1 a. Determine the closed-loop transfer function (Vo/Vi) of the system. b. Taking Kp = 1, find the unit-step response of the closed-loop system. Sketch out the unit-step response. c. Now if Kp is increased to 1.3, find the unit-step response. Compare the response with the case of Kp = 1 in part b. d. What is the effect of the P controller?