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);

the sphere also seems to shoot off in a forward direction on starting the gameā€¦ before i even click anywhere