MYTH: The average velocity of gas molecules in a container is useful in describing its kinematics. FACT: For large number of gas molecules in a container average velocity will be zero. Hence we use rms velocity.

 MYTH: The average velocity of gas molecules in a container is useful in describing its kinematics.

FACT: For large number of gas molecules in a container average velocity will be zero. Hence we use rms velocity.

Since, a large number of gas molecules is present in a container, therefore for velocity of any molecule there exists another molecule with an equal and opposite velocity As velocity is a vector quantity. Resultant velocity of all the molecules becomes zero, hence average velocity also vanishes.