Hi, I am making a 4 player pong game, and I want the ball to increase speed every 10 seconds. heres the code i have so far, im just not sure what to add to it to achieve this.

var temp : Vector3;


function Start() 
{

    gameObject.rigidbody.AddForce(500,0,500);
 }

function OnCollisionEnter(col : Collision)
{
    temp = gameObject.rigidbody.Velocity;
    Debug.Log("X: " + temp.x + " Y: " + temp.y);
    if(temp.x > 0)
    {
       gameObject.rigidbody.AddForce(-1000, 0, 0);
    }
    else if(temp.x <0)
    {
       gameObject.rigidbody.AddForce(1000, 0, 0);
    }
    if(temp.z > 0)
    {
       gameObject.rigidbody.AddForce(0, 0, -1000);
    }
    else if(temp.z <0)
    {
       gameObject.rigidbody.AddForce(0, 0, 1000);
    }
}


function Update()
{
var temp : Vector3 = gameObject.rigidbody.Velocity;
    if(temp.x > 0)
    {
       gameObject.rigidbody.AddForce(-1500, 0, 0);
    }
    else if(temp.x <0)
    {
       gameObject.rigidbody.AddForce(1500, 0, 0);
    }
    if(temp.z > 0)
    {
       gameObject.rigidbody.AddForce(0, 0, -1500);
    }
    else if(temp.z <0)
    {
       gameObject.rigidbody.AddForce(0, 0, 1500);
    }
}
    enter code here