Force script

public class Force : MonoBehaviour {

	public GameObject Prefab;

	public float power;
	public int objLimit;
	int objAdd;
	void Start () {

	}

	// Update is called once per frame
	void Update () {
		if (Input.GetButtonUp ("Jump")) {
                       if(objAdd != objLimit){
			GameObject instance = Instantiate (Prefab, transform.position, transform.rotation)as GameObject;
			Rigidbody rb=instance.GetComponent<Rigidbody>();
		        rb.AddForce (-transform.right*power,ForceMode.Impulse);
		        objAdd++;
                        }
	         }
         }
    }