To permit measurement of her speed, a skydiver carries a buzzer emitting a steady tone at 1 800 Hz. A friend on the ground at the landing site directly below listens to the amplified sound he receives. Assume that the air is calm and that the sound speed is 343 m/s, independent of altitude. While the skydiver is falling at terminal speed, her friend on the ground receives waves of frequency 2 150 Hz.
(a) What is the skydiver’s speed of descent?
(b) What If? Suppose the skydiver can hear the sound of the buzzer reflected from the ground. What frequency does she receive?