Hello Im new to flash kit and I was wondering if I could get some help with my code.

I'm trying to create a plunger for a pinball game I'm creating and kinda at a loss on
how to make one. Here's my code and thx in advance:

package
{
import flash.events.Event;
import flash.events.KeyboardEvent;
import flash.display.Sprite;
import flash.ui.Keyboard;
import flash.display.StageAlign;
import flash.display.StageScaleMode;

public class Pinball_Main extends Sprite
{
private var ball:Ball;
private var gravity:Number = 0.3;
private var bounce:Number = -0.3;
private var vx:Number = 0;
private var vy:Number = 0;
private var ay:Number = 0;
private var left:Number = 0;
private var top:Number = 0;
private var right:Number = stage.stageWidth;
private var bottom:Number = stage.stageHeight;


public function Pinball_Main()
{
// constructor code
init();
}
public function init():void
{
stage.scaleMode = StageScaleMode.NO_SCALE;
stage.align = StageAlign.TOP_LEFT;
ball = new Ball();
addChild(ball);
ball.x = stage.stageWidth / 2;
ball.y = stage.stageHeight / 2;
addEventListener(Event.ENTER_FRAME, onEnterFrame);
stage.addEventListener(KeyboardEvent.KEY_DOWN, onKeyDown);
stage.addEventListener(KeyboardEvent.KEY_UP, onKeyUp);
}
private function onKeyDown(event:KeyboardEvent):void
{
if(event.keyCode == Keyboard.SPACE)
{
ay = -1.5
}
}
private function onKeyUp(event:KeyboardEvent):void
{
ay = 0;
}

private function onEnterFrame(event:Event):void
{
ball.vy += ay;
ball.vy += gravity;
ball.y += ball.vy;
ball.x += ball.vx;

if (ball.x + ball.radius > stage.stageWidth)
{
ball.x = stage.stageWidth - ball.radius;
ball.vx *= bounce;
}
else if (ball.x - ball.radius < 0)
{
ball.x = ball.radius;
ball.vx *= bounce;
}

if (ball.y + ball.radius > stage.stageHeight)
{
ball.y = stage.stageHeight - ball.radius;
ball.vy *= bounce;
}
else if (ball.y - ball.radius < 0)
{
ball.y = ball.radius;
ball.vy *= bounce;
}
}

}

}