Question

A piano tuner strikes a tuning fork at the same time he strikes a piano key with a note of a similar pitch. If he hears 3 beats per second, and the tuning fork produces a standard 440 Hz tone. Then what was the frequency produced by the struck piano string?

Answer 1

f1-f2 = 3 beats per second = 3 Hz (since 1 beat/second = 60 beats/minute = 1 Hz).

Where, f1 = frequency of tuning fork, f2 = frequency produced by the piano.

Therefore,
f2 = f1 - 3 = 440 -3 = 437 Hz