SAT Subject Physics Practice Question 476: Answer and Explanation
7. A species of hummingbird beats its wings 3,300 times per minute. What frequency of sound will a nearby person hear when the hummingbird flies by?
A. .003 Hz
B. .018 Hz
C. 6 Hz
D. 55 Hz
E. 3300 Hz
Correct Answer: D
The correct answer is (D). The frequency at which the humming bird beats its wings is already given in beats per minute. To find the number of wing beats per second (Hz), divide the number of wing beats per minute by 60 seconds.