A tour boat equipped with a whistle of rest frequency 380 Hz departs a dock on a calm lake
PHYSICS · Multi-part · AP · Physics 2: Algebra-based · Waves Sound and Physical Optics · Waves Sound and Physical Optics
Problem
A tour boat equipped with a whistle of rest frequency 380 Hz departs a dock on a calm lake. A spectator stands on the dock as the boat first moves directly toward the spectator, passes at constant speed, and then moves directly away. The boat’s speed is 12 m/s, and the speed of sound in air is 343 m/s.
(a) Calculate the frequency heard by the spectator when the boat is moving toward the dock.
(b) Calculate the frequency heard by the spectator after the boat has passed and is moving directly away.
(c) Determine the numerical value (in hertz) of the change in frequency experienced by the spectator between the approaching and receding situations. Express your answer to three significant figures and include appropriate units.