A violin player hears four beats per second when she compares her note to a 523 Hz tuning fork. She can match the frequency of the tuning fork by tightening her string slightly. What was her initial frequency?
The violin player is trying to make the frequency of her playing similar to the tuning fork. Now she is able to hear two sound waves, the one from her violin and the other one from the fork. As the two sounds approach the ear, the alternating constructive interferences will cause the sound to have different intensities of perception. Meaning the other one may sound louder than the other. The player hears initially 4 beats per seconds which also means that the beat frequency is 4Hz. When she tightened the strings, she is able to copy the frequency of the tuning fork. The frequency therefore of the violin initially is 4 Hz less than the tuning fork or 519 Hz.