* Sound needs a medium to travel: Sound waves are vibrations that travel through a medium, like air, water, or solids. They cannot travel in a vacuum because there are no particles to vibrate.
* Velocity of sound in a vacuum is zero: Since there's nothing to vibrate in a vacuum, sound cannot travel at all, meaning its velocity is zero.
Therefore, the velocity of sound is not at its maximum in a vacuum; it's actually nonexistent.
