Stop moving Ball after respawn for seconds c#

Hey!

Im trying to get a ball to respawn with the keypress R, which is working fine! But when the ball respawn it still have the same movement speed as it had when it died. I have tried with a vectore3.zero, but it seem to just slow the ball. Is there a way to have the vectore3.zero, or another way to have the ball to totally stop moving for like 2 second after respawn (keypress R)?

GetComponent().velocity = Vector3.zero; is what is working to slow/stop the ball, but only when it's played in Void Update. it's being ignored in Void Start and get on error other places.

using UnityEngine; using System.Collections;

public class FallRespawn : MonoBehaviour {

  Vector3 respawn_Pos;
 
  void Start () {
      respawn_Pos = transform.position;
       GetComponent<Rigidbody>().velocity = Vector3.zero;
      
  }
 
  void Update () {
      if (Input.GetKeyDown(KeyCode.R))
          transform.position = respawn_Pos;
          
  }
  

}

Hope someone can help me out! :)