Final answer:
We can't hear the sound produced by every vibrating body because the sound waves they produce may be outside the range of frequencies that our ears can perceive or may have extremely low amplitudes.
Step-by-step explanation:
Sounds waves are characterized by their frequency, wavelength, period, and amplitude. The frequency of a sound wave determines its pitch, and the human ear can perceive sounds with frequencies between 30 and 20,000 Hz. Therefore, option 1, the sound waves produced are of very low frequency, is incorrect.
Similarly, the amplitude of a sound wave determines its loudness, and most sounds we encounter have a range of amplitudes. So option 3, the sound waves produced are of very low amplitude, is also incorrect.
In conclusion, we can't hear the sound produced by every vibrating body because the sound waves they produce may be outside the range of frequencies that our ears can perceive or may have extremely low amplitudes.