Sphere movement very erratic and uncontrollable.

Okay, I feel like an idiot asking so many questions. But if you have seen my questions before I was asking how to get a sphere to rotate physically, and how to get a camera to follow it. Both of those were done Yay! But i'm currently faced with a problem. When it starts to rotate, and move. It doesn't seem to stop. Go ahead and open the scripts I post and try it to see what I mean. I have no idea why it's doing it. I thought making it relative would work but I guess not. Here is my code

Sphere Movement:

 function FixedUpdate () {
 if (Input.GetButton("W"))
 {
 
 rigidbody.AddRelativeTorque (0, 0, 2);
 
 rigidbody.AddRelativeForce (0, 0, 2);
 }
 
 
 if (Input.GetButton("S"))
 {
 
 rigidbody.AddRelativeTorque (0, 0, -2);
 rigidbody.AddRelativeForce (0, 0, -2);
 }
 
 if (Input.GetButton("A"))
 {
 rigidbody.AddRelativeTorque (-2, 0, 0);
 rigidbody.AddRelativeForce (-2, 0, 0);
 }
 
 
 if (Input.GetButton("D"))
 {
 rigidbody.AddRelativeTorque (2, 0, 0);
 rigidbody.AddRelativeForce (2, 0, 0);
 }
 }

Camera:

 var target: Transform;
 var damp: float = 0.2;
 var distance: float = 50;
 
 function Update(){
 
     damp = Mathf.Clamp(damp, 0.01, 10); // clamps damping factor
     var pCam = transform.position;
     var pTarget = target.position;
     var diff: Vector3 = pTarget - pCam;  // diff = difference between positions
     var dist = diff.magnitude;  // dist = distance between them
     if (Mathf.Abs(diff.y) < 0.7*distance){
         diff.y = 0;  // doesn't modify camera height unless angle > 45
     } 
     if (dist>distance){ // if distance too big...
         diff *= 1-distance/dist; // diff = position error
         // move a FPS independent little step towards the ideal position
         transform.position = pCam + diff * Time.deltaTime/damp;
     }
     transform.LookAt(pTarget);
 }

Please, to really understand what I mean. Make a blank sphere on a map with a camera and apply these scripts.