We can’t hear the sound of vibrations of a pendulum. Reason out.

1. First, let's understand what a pendulum is. A pendulum is a weight suspended from a fixed point that can swing back and forth.

2. When a pendulum swings, it creates vibrations or oscillations. These vibrations are caused by the force of gravity acting on the weight and the tension in the string or rod that holds the weight.

3. Vibrations are a form of mechanical energy that can travel through a medium, such as air or water. In order for us to hear a sound, these vibrations need to be transmitted to our ears.

4. However, the vibrations created by a pendulum are typically very small and do not generate enough energy to travel through the air and reach our ears as sound waves.

5. Additionally, the frequency of the pendulum's vibrations is usually too low for our ears to detect. The human ear can typically hear sounds with frequencies between 20 Hz and 20,000 Hz, while the vibrations of a pendulum usually have much lower frequencies.

6. Therefore, even though a pendulum creates vibrations, we cannot hear them because they do not have enough energy to travel through the air as sound waves and their frequencies are outside the range of human hearing.

In conclusion, the reason we can't hear the sound of vibrations of a pendulum is because the vibrations are too small and have frequencies that are outside the range of human hearing.