In this scenario, the student is a passive participant in the process. The information learned is impersonal. Clearly, the teacher is in control of the learning process; his or her interests dictate what and how fast the students learn.
The answer in all three cases is that rudder is used to help maintain stability in the roll. A little rudder at just the right time can help keep the nose up in a slow roll or even an aileron roll, as the plane rotates through the sideways portions of the roll when gravity is otherwise not countered.
Servo Motor Applications. Servos are used in radio-controlled airplanes to position control surfaces like elevators, rudders, walking a robot, or operating grippers. Servo motors are small, have built-in control circuitry and have good power for their size.