Problem with Ball Bouncing after Collision

I am Making a Circle Pong Clone, in that the ball doesn't have a Good Bouncing behaviour i want ball behaviour like in this Video https://www.youtube.com/watch?v=nFnvaThOS30 here is the Code of Ball

Here is what i have Achieved https://drive.google.com/open?id=1kJeD3OfBn6XWoFB15Lern39lZ2oX9EWZ

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 public class Ball : MonoBehaviour
 {
     public Rigidbody2D rb;
     public Transform centerPoint;
     public float force;
     public Vector2 direction;
 
     Vector3 startPosition;
     float angle;
 
     void Start()
     {
         startPosition = transform.position;
         rb = GetComponent<Rigidbody2D>();
         Invoke("Move", 2f);
         InvokeRepeating("GameOver", 1.0f, 0.8f);
     }
 
     void Move()
     {
         direction = new Vector2(0.5f, -1f);
         rb.AddForce(direction * force);
     }
     void OnCollisionEnter2D(Collision2D col)
     {
         Vector2 norm = col.contacts[0].normal;
         Bounce(norm);
 
     }
     void Bounce(Vector2 normal)
     {
         normal = normal.normalized;
         Vector2 newDirection = Vector2.Reflect(direction, normal);
         newDirection = newDirection.normalized;
         rb.AddForce(newDirection * force);
         direction = newDirection;
 
        // angle = Vector2.Angle()
 
     }
 
     //void CalculateAngel()
     //{
 
     //}
     void GameOver()
     {
         if (Vector3.Distance(transform.position, centerPoint.position) > 1.2f)
         {
             rb.Sleep();
             transform.position = startPosition;
             CancelInvoke("GameOver");
             Invoke("Restart",0.1f);
         }
     }
 
     void Restart()
     {
         Invoke("Move", 2f);
         InvokeRepeating("GameOver", 2.0f, 0.8f);
     }
 }

This Script is added to Ball along with Rigidbody & Circle Collider with a PhysicsMaterial2D Added Anyhelp