package
  {
          import flash.display.Sprite;
          import flash.events.Event;
          
          public class @ax-animation-ch05-Acceleration1 extends Sprite
          {
                  private var ball:animation_ch05_Ball;
                  private var vx:Number = 0;
                  private var ax:Number = .2;
                  
                  public function @ax-animation-ch05-Acceleration1()
                  {
                          init();
                  }
                  
                  private function init():void
                  {
                          ball = new animation_ch05_Ball();
                          addChild(ball);
                          ball.x = 50;
                          ball.y = 100;
                          addEventListener(Event.ENTER_FRAME, onEnterFrame);
                  }
                  private function onEnterFrame(event:Event):void
                  {
                          vx += ax;
                          ball.x += vx;
                  }
          }
  }