Question

You are standing at the end of a runway at an airport with the intent of analyzing sound produced by airplanes while they are landing. A plane lands on the runway 1000 m in front of you and you begin recording the sound produced by the plane. The pilot slows the plane to a stop 100 m in front of you. During this time the average frequency of the sound that you record changes from 570 Hz as the plane is touching down to 450 Hz as the plane comes to a stop. You speak to the pilot afterward and they say the plane sounded the same to them the entire time. a) Explain why the sound frequency you recorded changed while it did not change for the pilot. b) Use the details of the sound you recorded to determine the speed of the plane at the moment it touched down on the runway.

Answer 1