Pendulums

var mouseSpeedX:Number = 0;
var prevX:Number = 0;

var pends:Array = new Array();
for (var i:int = 0; i<10; i++){
       pends.push(makePendulum(100+ i * 40, 100, 15, 100 + i * 10));
}

addEventListener(Event.ENTER_FRAME, onRun);
function onRun(evt:Event):void {
       // mouseSpeed
       mouseSpeedX = prevX - mouseX;
       prevX = mouseX;

       for (var i:int = 0; i<pends.length; i++) pends[i]();
}

function makePendulum(xp:Number, yp:Number, rad:Number, leng:Number):Function {
       var rot:Number = 0;
       var rotDest :Number = 0;
       var rotVel:Number = 0
       var string:Shape = Shape(addChild(new Shape()));
       var ball:Sprite = Sprite(addChild(new Sprite()));
       ball.buttonMode = true;
       with(ball.graphics) beginFill(0xFF0000), drawCircle(0,leng, rad);
       ball.x = xp;
       ball.y = yp;
       string.x = ball.x;
       string.y = ball.y;
       ball.addEventListener(MouseEvent.ROLL_OVER,function(){
             rotDest = mouseSpeedX;
       });
       return function(){
           // force rotDest back to 0
           rotDest *= .8;
               // elasticity (hooke's)
               rotVel += (-1.9 * (rot - rotDest) - rotVel) / 4;
               rot += rotVel
               ball.rotation = rot;
               // draw string:
               string.graphics.clear();
               string.graphics.lineStyle(0,0);
               var pnt:Point = ball.localToGlobal(new Point(0, leng))
               string.graphics.curveTo(0, leng / 2, pnt.x - ball.x, pnt.y-ball.y);
  }
}

This is a variation on something I wrote in response to a student question. It creates a few pendulums that can be pushed with the mouse.