The relative linear velocity of the two colliding objects (Read Only).
// Play a sound when we hit an object with a big velocity using UnityEngine; using System.Collections;
public class ExampleClass : MonoBehaviour { AudioSource audio;
void Start() { audio = GetComponent<AudioSource>(); }
void OnCollisionEnter(Collision collision) { if (collision.relativeVelocity.magnitude > 2) audio.Play(); } }