[5 pts] Consider the actuator disk model, as discussed in class and displayed below. Assume an axial induction factor equal to 0.23. Stream tube boundary Actuator disk U1 U2 U3 U4 1 23 a. What is the ratio of the flow velocity at station 2 to the free-stream velocity? b. What is the ratio of the flow velocity at station 4 to the free-stream velocity? c. What is the coefficient of pressure right before the rotor? d. What is the coefficient of pressure right after the rotor? e. Calculate the thrust and power coefficients.