Final answer:
The provided information is insufficient to accurately define when the second segment (S2) begins and is completed in an aircraft's landing procedure, as it lacks proper aviation context.
Step-by-step explanation:
The question appears to be concerning the phases of an aircraft's landing procedure, particularly the second segment (S2). This segment likely refers to a part of the flight path after landing. However, the information provided doesn't directly allow for determining when the second segment begins and is completed since it talks about an airplane's landing velocity and the need to slow down before heading to the terminal. Typically, the second segment, in aviation terms, relates to the climb performance after takeoff up to a certain height. Therefore, without proper context or additional aviation-related information, providing an accurate completion point for the second segment is difficult. The second segment usually begins after liftoff and is completed upon reaching the acceleration height, where the aircraft begins to accelerate and retract the landing gear.
The subject of this question is physics. The question is related to the calculation of the completion time of the second segment (S2), which involves the landing gear retraction and the selected acceleration height. To answer this question, we need to consider the initial velocity and final velocity of the airplane during landing and apply the principles of motion.