Question

a. Why don't we hear the sound of oscillation of second
pendulum?​

Answer 1

Answer:

because the frequency is too low for humans to hear.

Explanation:

Answer 2

Answer:

we cannot hear the sound produced due to vibrations of a seconds' pendulum.

Explanation:

This is because the frequency of sound produced as a result of vibrations of seconds' pendulum is 0.5Hz0.5Hz which is infrasonic sound.