var other : GameObject;
other.rigidbody.AddForce(1,1,1);

using UnityEngine;
using System.Collections;

public class example : MonoBehaviour {
public GameObject other;
void Awake() {
other.rigidbody.AddForce(1, 1, 1);
}
}

import UnityEngine
import System.Collections

class example(MonoBehaviour):

public other as GameObject

def Awake():
other.rigidbody.AddForce(1, 1, 1)