Final answer:
Beat frequencies are calculated by finding the differences between pairs of frequencies, and for the piano keys F, F-sharp, and G played simultaneously, these are 21 Hz, 22 Hz, and 43 Hz.
Step-by-step explanation:
When three adjacent keys on a piano (F, F-sharp, and G) are struck simultaneously, they produce the frequencies of 349, 370, and 392 Hz. The beat frequencies that these combinations create can be found by calculating the differences between each pair of frequencies. For F (349 Hz) and F-sharp (370 Hz), the beat frequency is 370 Hz - 349 Hz which equals 21 Hz. Similarly, for F-sharp (370 Hz) and G (392 Hz), the beat frequency is 392 Hz - 370 Hz which equals 22 Hz. Lastly, for F (349 Hz) and G (392 Hz), the beat frequency is 392 Hz - 349 Hz which equals 43 Hz. Therefore, this discordant combination of keys produces beat frequencies at 21 Hz, 22 Hz, and 43 Hz.