Question

How is the direction of propagation of medium particles related to the direction of propagation of a longitudinal wave?

Answer 1

1. There are two types of waves - longitudinal waves and transverse waves.
2. In a longitudinal wave, medium particles vibrate about their mean position along the direction of the path of propagation of the wave.

Hence, the direction of propagation of medium particles is along the direction of propagation of a longitudinal wave.