Collision2D.relativeVelocity
var relativeVelocity: Vector2;
Description

The relative linear velocity of the two colliding objects (Read Only).

	// Play a sound when we hit an object with a big velocity
	function OnCollisionEnter2D(collision : Collision2D) {
		if (collision.relativeVelocity.magnitude > 2)
			audio.Play();
	}