The capstan drive system of the previous problems has a disturbance due to changes in the part that is being machined as material is removed. The controller is an amplifier Gc(s) - Ka. Evaluate the effect of a unit step disturbance, and determine the best value of the amplifier gain so that the overshoot to a step command r(t) = A, t > 0 is less than 5%, while reducing the effect of the disturbance as much as possible.