Error Code Instance Of An Object

Questions & Answers
1

This is my code

        private Rigidbody rb;
         
          void start()
          {
                         rb = GetComponent<Rigidbody>();
          }
         
          void FixedUpdate ()
          {
                         float moveHorizontal = Input.GetAxis ("Horizontal");
                         float moveVertical = Input.GetAxis ("Vertical");
                        
                         Vector3 movement = new Vector3 (moveHorizontal, 0.0f, moveVertical );
                        
                         rb.AddForce (movement);
                        
          }

}

Why do I get a error code that says:
NullReferenceException: Object reference not set to an instance of an object
PlayerMovement.FixedUpdate () (at Assets/PLayerMovement.cs:20)

I would like to know 2 things:

  1. Why did I get this error?
  2. How do I fix this error

Additional Info:
I am a beginner and am learning unity through the video tutorials. This was the roll a ball tutorial. If possible, please copy this code, fix it, and post it in the answers and explain what happened in simple language.

Many Thanks :slight_smile:

2

You have start() it needs to be Start(), because it’s lowercase it’s not executed thus rb is not defined.