I am attempting to make a scroller that scrolls a long image along an x-axis and a few other elements. The problem I am having is that I want to add momentum to the image that scrolls and I am not sure how to go about doing this... can someone point me in the right direction? Here is my actionscript so far:

main.navigation.dragbar.onPress = function(){
	this.startDrag(false, -80, 0, 285, 0);

main.navigation.dragbar.onRelease = function(){

function moveBG(){
	main.bg.onEnterFrame = function(){
		navigationX = main.navigation.dragbar._x * 4.25;
		if(main.navigation.dragbar._x < 1){}else{
		main.bg._x = (-main.navigation.dragbar._x) * 4.25};