You are standing still on a mountain top. The wind is blowing toward the north with a velocity of 91 m/s. An airplane is flying directly at you from the north (traveling south) at a velocity of 100 m/s. The engines on the airplane make a whining sound at a frequency of 2,000 Hz when the plane and the observer are at rest with respect to the surrounding air. What frequency do you hear as the plane approaches you on this windy day