How to find a Rigidbody component on a specific object by object name or tag!?

Is it Possible? You can do this as for the transforms but for the rigidbody:

  void Start () 
     GameObject.Find("Name Object").transform;

For Rigidbody (or any other component) you use GetComponent()

So in your case it would be GameObject.Find(“Name Object”).GetComponent()

Just a note here is that searching game objects by name or tag is strongly discouraged, simply because it’s extremely slow, especially with bigger scenes.