missing method exception method not found

function Awake ()
Rigidbody.addForce(4,4,0, ForceMode.Impulse);

Use lowercase rigidbody.

Uppercase is for declaring vars, or using “class” var/functions. For examples, use lower-case transform.position to read yourself, but uppercase var target: Transform; to declare a target var. Uppercase Vector3.right because you’re talking about the built-in right and not a particular vector3’s right.

It’s not really a lower/upper rule. It’s just that Unity named your Transform variable as lower-case transform, and so on. It’s like naming your cat “cat.”

The exact error is that uppercase Rigidbody.AddForce(...) thinks you’re trying to use the (non-existant) generic AddForce command on no rigidbody in particular. In the docs, “functions” use lower-case and are “on” the thing in front of them (like transform.rotate) and “class functions” are uppercase and are like saying to look in that folder for this built-in.