Question

Why oscillation of Pendulum is not audible for human being?

Answer 1

If something vibrates at a frequency of or in between 20Hz to 20KHz, we can hear it otherwise we can’t. because our ear can hear only this frequency range.

OK, now according to this question the oscillation of pendulum is lees than the 20Hz(e.i. the swing of a pendulum isn’t grater than the 20 times in 1 second ).

that’s why we can’t hear the sound of pendulum oscillation.