I'm currently having trouble understanding the math behind flicking and object and how to execute it in javascript..

I currently am using:

Update Function
var time = this.launchTimer.delta();
		
		var ball = this.getEntitiesByType(EntityPlayer)[0];
		if (ig.input.pressed('leftButton')){
			this.launchTimer.reset();
			xStart = nX;
			yStart = nY;
		}
		if (ig.input.released('leftButton')){
			xEnd = nX;
			yEnd = nY;
			yresult = (yEnd - yStart);
			xresult = xEnd - xStart;
			console.log("L " + xresult);
			ball.launch(xresult, yresult);
		}


var nX;
var nY;
var xStart;
var xEnd;
var xresult;

var yStart;
var yEnd;
var yresult;
Canvas.addEventListener('touchstart', function(event){
	ig.input.actions['mouse']=true;
	nX=event.touches[0].pageX;
	nY=event.touches[0].pageY;
}, true);
Canvas.addEventListener('touchmove', function(event){
	ig.input.actions['mouse']=true;
	nX=event.touches[0].pageX;
	nY=event.touches[0].pageY;  
}, false);
Canvas.addEventListener('touchend', function(event){
	ig.input.released['mouse'] = true;
	nX=event.touches[0].pageX;
	nY=event.touches[0].pageY;    
},false);

My issues are in:
The Angle and how to calculate it
The Speed, am I calculating it correctly?
Acceleration, the entity starts slow and accels, is there a way to have it start faster and slow down with the friction?