Adding inertia on looped onRollOver

Gday yall…
I need to add inertia (gradual slowing down of the clip before it comes to a stop) to the following code :

up.onRollOver = function () {
_parent.pages.onEnterFrame = function(){
_parent.pages._y -= 3;
}
}

This code is a looped onRollOver, sa long as the mouse cursor is within “up”, the movieClip moves up 3 pix at a time. I need it to slow down simulating inertia when the cursor is removed.

I know a code that usually works {

f=0.3;
xdest = 300;
onEnterFrame = function () {
movingClip_mc._x += (xdest - movingClip_mc._x) * f;
}
}

But in this case it doesn’t…
Any ideas are gladly welcome.