Final answer:
The resultant velocity of an airplane flying due north at 100 m/s with a wind blowing due south at 30 m/s is 70 m/s due north. This phenomenon exemplifies vector addition in the context of air travel.
Step-by-step explanation:
In this case, the airplane is moving due north at 100 m/s, and wind blows due south at 30 m/s. Since velocity is a vector quantity with both magnitude and direction, when the wind's velocity is due south, it would effectively reduce the airplane's speed when it encounters a headwind. To find the resultant velocity, subtract the wind's speed from the airplane's speed because they are moving in opposing directions. This calculation gives us the magnitude of the resultant velocity: Resultant velocity = Airplane's speed - Wind's speed = 100 m/s - 30 m/s = 70 m/s due north. Therefore, the correct answer to the student's question is that the resultant velocity of the airplane is 70 m/s due north.