Need help when arrow hits collider

hello all iv been making a rpg game and im making a bow system but i have a problem with when my arrow hits a collider for it to stop moving im new to scripting and i dont no what i should use? this is my script at the moment

    var timeOut = 10.0;
static var ARROWSPEED = 100.0;

function Awake () {
    Invoke ("DestroyNow", timeOut);
}

function Update () 
{
    rigidbody.AddForce(transform.forward * ARROWSPEED);
}

function DestroyNow () {
    DestroyObject (gameObject);
}

also how would i make it that after the arrow has stopped moving for it to change the timeout variable to 100 seconds instead of 10 seconds if you can help that will be awesome thanks

Try this code

static var arrowSpeed = 100.0;

function Start() 
{
    rigidbody.AddForce(transform.forward * arrowSpeed);
}

function OnCollisionEnter()
{
    Destroy(rigidbody);
}