When i use Fixed Update rigidbody get null...i don't know why .help me...Thank you

[Mohd-Rizwan]

[Kishotta]

This is a depreciated method for accessing a Rigidbody component attached to your GameObject.

You should either use:

GetComponent<Rigidbody> () = ... ;

any time you access the Rigidbody or:

Rigidbody rb;
void Awake () {
    rb = GetComponent<Rigidbody> ();
}
void FixedUpdate () {
    rb.velocity = ... ;
}

And then you can use rb as a reference to the attached Rigidbody.