Ball.cs

using UnityEngine;
using System.Collections;

public class Ball : MonoBehaviour {

    public float ballIntVel = 600f;

    private Rigidbody rb;
    private bool ballInPlay;


	// Use this for initialization
	void Awake () {
        rb = GetComponent<Rigidbody>();
	
	}
	
	// Update is called once per frame
	void FixedUpdate () {
        if (Input.GetButtonDown ("Fire1") && ballInPlay == false) {
            transform.parent = null;
            ballInPlay = true;
            rb.isKinematic = false;
            rb.AddForce(new Vector3(ballIntVel, ballIntVel, 0));
       
        }
	
	}
}