Question 2 Consider the system shown in Figure Q2, where W is a unit step disturbance and R is a unit step input. 0.4 W s+1 + R Y 1 + K 10 s+1 S Figure Q2 (a) Find the expression of E(s)=R(s)-Y(s) in terms of R and W; (5 marks) (b) Find the steady state error in y(t) in terms of K (Hint: E(s)=R(s)-Y(s)); (3 marks) (c) Find the value for K so that the steady state error due to w(t) is less than 0.01; (6 marks) (d) In order to eliminate the steady state error, show whether a PI controller can be successful instead of the proportional controller K? (6 marks)