动量守恒计算

package cn.d
{
    import flash.display.Sprite;
    import flash.events.Event;
    
    public class Billiard1 extends Sprite
    {
        private var ball10:Ball;
        private var ball11:Ball
        
        public function Billiard1()
        {
            
            init();
        }
        
        private function init():void
        {
            
            ball10=new Ball(20);
            ball10.x=50;
            ball10.y=stage.stageHeight/2;
            ball10.mass=2;
            ball10.vx=1;
            
            this.addChild(ball10)
            
            ball11=new Ball(30);
            ball11.x=300;
            ball11.y=stage.stageHeight/2;
            ball11.mass=1;
            ball11.vx=-1;
            
            this.addChild(ball11)
            
            this.addEventListener(Event.ENTER_FRAME,onEnterFrame);
        }
        
        private function onEnterFrame(e:Event):void
        {
            ball10.x+=ball10.vx;
            ball11.x+=ball11.vx;
            
            var dic:Number=ball11.x-ball10.x;
            
            if(Math.abs(dic)<ball10.radius+ball11.radius)
            {
                var v0:Number=((ball10.mass-ball11.mass)*ball10.vx+2*ball11.mass*ball11.vx)/(ball10.mass+ball11.mass);
                var v1:Number=((ball11.mass-ball10.mass)*ball11.vx+2*ball10.mass*ball10.vx)/(ball10.mass+ball11.mass);
                
                ball10.vx=v0;
                ball11.vx=v1;
                
                ball10.x+=ball10.vx;
                ball11.y+=ball11.vy;
                
            }
        }
    }
}