This version of Unity is unsupported.
Removed

Component.rigidbody

Obsolete Property rigidbody has been deprecated. Use GetComponent<Rigidbody>() instead. public Component rigidbody;

Description

The Rigidbody attached to this GameObject. (Null if there is none attached).

using UnityEngine;

public class Example : MonoBehaviour { void Start() { GetComponent<Rigidbody>().AddForce(1, 1, 1); } }