a Whistle Is Whirled Around in a Horizontal Circle

Multiple Choice

. A whistle is whirled around in a horizontal circle 120 times a minute at the end of a piece of string 1.5 m in length.If the standard frequency of the whistle is 550 Hz,calculate the difference between the highest and lowest frequencies heard by a stationary observer (assume the speed of sound in air = 343 m/s) .

A) 58 Hz
B) 64 Hz
C) 61 Hz
D) 32 Hz
E) 29 Hz