Object movement

i am doing a tut out of a book but im stuck.

This code below works fine. It gives an object named bal some speed when you drag it. The thing is it gives it speed when you just click it as well. I want to give is speed only when it is really dragged. This code is on a object named “bal”

on (press) {
    startDrag(this, false, _root.xpos-50, _root.ypos, _root.xpos, _root.ypos); 
}
on (release) {
        stopDrag();
        _root.v = (_root.xpos-_x)/5;
}
onClipEvent (enterFrame) {
    _root.sV = "snelheid = "+_root.v;
    xpos += _root.v *= 1.1;
    if (hitTest(_root.doel)) {
        _root.doel._visible = false;
        _root.geraakt = true;
    }
    if (_root.geraakt) {
        _root.v = 0;
    }
}

This is code on the main timeline:

with (bal) {
    ypos = _y;
    xpos = _x;
}
var v:Number = 0; // snelheid
var geraakt:Boolean = false; // doel geraakt?

This is something i tried:

on (release) {

    stopDrag();
if (_x == 0) {
    _root.v = 0;
}

else {_root.v = (_root.xpos-_x)/5;}
}

hope someone got any tips for me to better understand it all.