ball script

using UnityEngine;
using System.Collections;

public class ball : MonoBehaviour {

    public Rigidbody2D rb;

    void Start ()
    {
        this.GetComponent<Rigidbody2D>().AddForce (-transform.up * 100f);
    }

    void Update ()
    {
        if ((transform.position.x > 9.40f) || (transform.position.x < -9.40f))
        {
            transform.position=new Vector2(0.0f,0.0f);
        }
        if ((transform.position.y > 5.55f) || (transform.position.y < -5.55f))
        {
            transform.position=new Vector2(0.0f,0.0f);
        }
    }
}