GameObject fall Slowly [C#]

Hey eveybody ! Today i'm making a car. Alls my 3D gameObjects are in an Empty GameObject who have the rigidbody (with 1000 in Mass) and my playerControler. But the fact is that my GameObject fall very Slowly and i check on the internet but nothing work....

this is my script :

using UnityEngine; using System.Collections; using UnityEngine.Networking;

public class PlayerControler : NetworkBehaviour { Transform trans; // Used to cache the transform Rigidbody body; // Used to cache the RigidBody float hInput; float vInput; float rotationSpeed = 90f; // float fallVelocity; public GameObject phareGauche; public GameObject phareDroit;

 void Awake()
 {
     trans = transform;
     body = GetComponent<Rigidbody>();
 }

 // Update is called once per frame
 void Update()
 {
     if (isLocalPlayer == false) return;// Don't check input if this isn't running
                                        // on the local player object


     /*fallVelocity = gameObject.GetComponent<Rigidbody>().velocity.z;
     gameObject.GetComponent<Rigidbody>().velocity += Vector3.down * fallVelocity;*/

     if (Input.GetAxis("Vertical") < 0)
     {
         phareDroit.GetComponent<Renderer>().material.color = new Color(255f, 142f, 0f);
         phareGauche.GetComponent<Renderer>().material.color = new Color(255f, 142f, 0f);
     } else
     {
         phareDroit.GetComponent<Renderer>().material.color = new Color(214f, 217f, 224f);
         phareGauche.GetComponent<Renderer>().material.color = new Color(214f, 217f, 224f);
     }

     hInput = Input.GetAxis("Horizontal");
     vInput = Input.GetAxis("Vertical");
 }

 void FixedUpdate()
 {
     if (isLocalPlayer == false) return;// Don't check input if this isn't running
                                        // on the local player object
                                        // Remove unwanted forces resulting from collisions
     body.velocity = Vector3.zero;
     body.angularVelocity = Vector3.zero;

     // Handle rotation
     var rot = body.rotation.eulerAngles;
     rot.y += hInput * rotationSpeed * Time.deltaTime;
     body.MoveRotation(Quaternion.Euler(rot));

     // Handle forward movement
     body.MovePosition(body.position + vInput * trans.forward * 5f * Time.deltaTime);
 }

}

Thank you, bye !