A small aerial drone searching a wilderness area emits a steady 2.00 kHz tone from an…
PHYSICS · Multi-part · AP · Physics 2: Algebra-based · Waves Sound and Physical Optics · Waves Sound and Physical Optics
Problem
A small aerial drone searching a wilderness area emits a steady 2.00 kHz tone from an onboard loudspeaker to help ground teams locate it. The drone flies at 10.0 m/s directly toward a rescue worker who, in turn, jogs 3.00 m/s toward the drone along the same straight line. After the drone passes, both maintain their respective speeds but now move directly away from each other. Assume still air with a sound speed of 340 m/s.
(a) Determine the frequency heard by the rescue worker just before the drone reaches her.
(b) Determine the frequency heard by the rescue worker immediately after the drone has passed and is moving directly away.
(c) Several seconds later the drone’s tone reflects from a cliff face located beyond the worker. Treat the cliff as a perfectly reflecting surface fixed to the ground. Calculate the frequency the worker hears for the echo returning from the cliff after reflection of the drone’s tone.