How to apply force to a clone upon instantiation?

I have been trying to get a clone of my ball game object to have force applied to it upon spawning, but I haven’t been able to figure out how to fit it into my code. Speaking of which, here is my code:

using UnityEngine;
using System.Collections;

public class Spawning : MonoBehaviour
{
	public GameObject ball;
	public Rigidbody rb;
	public float spawnRate;
	public int ballCount;
	public float speed;
	public Vector2 movement;

	void Awake () {
		rb = GetComponent<Rigidbody> ();
	}


	void Start () {
		while(ballCount >= 0 && spawnRate <= 10)
			InvokeRepeating ("SpawningClones", 5, 2);

	}

	void SpawningClones (){
		Instantiate (ball, new Vector3 (UnityEngine.Random.Range (-2.22f, 2.22f), UnityEngine.Random.Range (3.8f, 4.8f)), Quaternion.identity);
	}
	void FixedUpdate () {
		spawnRate += Time.deltaTime;
		Vector2 movement = new Vector2 (UnityEngine.Random.Range (-10 * speed, 10 * speed), UnityEngine.Random.Range (-10 * speed, 10 * speed));
		spawnRate = 0;
		ballCount += 1;


	}
}
//this is what I would like to put into my code, but I don't know where. I tried putting it into the FixedUpdate method, but that didn't work: rb.AddForce (movement * 1);

Do you want to apply the force in the SpawningClones method?
If so, this may work:

using UnityEngine;

    void SpawningClones (){
             GameObject clone = (GameObject)Instantiate (ball, new Vector3 (UnityEngine.Random.Range (-2.22f, 2.22f), UnityEngine.Random.Range (3.8f, 4.8f)), Quaternion.identity);
    clone.rigidbody.addForce(INSERT_DIRECTION_HERE);
         }

GameObject clone = Instantiate (ball, new Vector3 (UnityEngine.Random.Range (-2.22f, 2.22f), UnityEngine.Random.Range (3.8f, 4.8f)), Quaternion.identity) as GameObject;
clone.rigidbody.addForce( // add some stuff);