Створити і штовхнути

     public GameObject bullet;

     void Start () {

          InvokeRepeating("F1", 1.0f, 3.0f); 

     }

     void F1 () {          

           GameObject go = Instantiate(bullet, transform.position, Quaternion.Euler(0, 0, 0)) as GameObject;

           go.GetComponent<Rigidbody>().AddForce(new Vector3(1, 1, 0) * 250);

           Destroy(go, 3.0f);

     }