How to get right Physics with Follow on click

I got a sphere object to follow my mouse while click and dragging. However it just glides without rolling towards my mouse. Is it possible to add a rigidbody to this and so make it rotate?

Something like : GetComponent.().AddTorque(direction * MoveSpeed * Time.deltaTime, ForceMode.Acceleration); ??

This is my current code:

 #pragma strict
 
 var smooth:int; // Determines how quickly object moves towards position
  
 private var targetPosition:Vector3;
  
 function Update () {
     if(Input.GetMouseButton(0))
     {
         var playerPlane = new Plane(Vector3.up, transform.position);
         var ray = Camera.main.ScreenPointToRay (Input.mousePosition);
         var hitdist = 0.0;
         
          
         if (playerPlane.Raycast (ray, hitdist)) {
             var targetPoint = ray.GetPoint(hitdist);
             targetPosition = ray.GetPoint(hitdist);
             var targetRotation = Quaternion.LookRotation(targetPoint - transform.position);
             transform.rotation = targetRotation;
         }
     }
  
     transform.position = Vector3.Lerp (transform.position, targetPosition, Time.deltaTime * smooth);