[Герыч]

я ж говорю, у тя было:

				dx = (pt[i].x - pt[i].old_x);
				dy = (pt[i].y - pt[i].old_y) + grav;
				pt[i].old_x = pt[i].x;
				pt[i].old_y = pt[i].y;
				pt[i].x += dx/1.1;
				pt[i].y += dy/1.1;

а я сделал

				dx = (pt[i].xx - pt[i].old_x);
				dy = (pt[i].yy - pt[i].old_y);
				pt[i].old_x = pt[i].xx;
				pt[i].old_y = pt[i].yy;
				pt[i].xx += dx;
				pt[i].yy += dy+grav*timeSqr;

я тут dx и dy чуток по-другому считаю.. и тут нет силы трения

кстати, что значит 1.1 тут:

				pt[i].x += dx/1.1;
				pt[i].y += dy/1.1;

Добавлено через 3 часа 9 минут
Сделал "слабые связи" всмысле как верёвка, а не палка постоянной длины:

package gerich.verlet
{
	import flash.display.Shape;
	import flash.display.Sprite;
	import flash.events.Event;
	import flash.events.MouseEvent;
 
	public class Main extends Sprite
	{
		private var pt:Array = new Array();
		private var joints:Array = new Array();
		private var mousejoints:Array = new Array();
		private var particles:Sprite = new Sprite();
		private var canvas:Shape = new Shape();
		private var grav:Number = 100;
		private var timeSqr:Number;
 
		// ========================================================== //
		public function Main():void
		{
			stage.frameRate = 40;
 
			timeSqr=1/stage.frameRate;timeSqr*=timeSqr;
 
			addChild(canvas);
 
			addChild(particles);
 
			pt.push(new Particle(270,150));
			pt.push(new Particle(270,175));
 
			joints.push(new WeakMouseJoint(pt[0], pt[1], 10));
 
			for (var j:int=1;j<100;j++)
			{
				pt.push(new Particle(270,175));
				joints.push(new WeakJoint(pt[j], pt[j+1], 10));
			}
 
			for (var i in joints)
			{
				if(joints[i] is MouseJoint)
					mousejoints.push(joints[i]);
			}
 
			for (var i in pt)
			{
				particles.addChild(pt[i]);
			}
 
			addEventListener(Event.ENTER_FRAME, checkJoints);
			addEventListener(Event.ENTER_FRAME, ptMouse);
		}
		// ========================================================== //
		private function checkJoints(event:Event):void
		{
			var dx:Number;
			var dy:Number;
 
			canvas.graphics.clear();
 
			// Gravity
 
			for (var i in pt)
			{
				dx = (pt[i].xx - pt[i].old_x);
				dy = (pt[i].yy - pt[i].old_y);
				pt[i].old_x = pt[i].xx;
				pt[i].old_y = pt[i].yy;
				pt[i].xx += dx;
				pt[i].yy += (dy+grav*timeSqr);
			}
 
			// Joints
 
			for (var z:int=0; z<10; z++)
			{
				for (var i in joints)
				{
					joints[i].Apply();
				}
				for (var i in pt)
				{
					pt[i].xx=Math.max(pt[i].xx,0);
					pt[i].xx=Math.min(pt[i].xx,stage.stageWidth);
					pt[i].yy=Math.max(pt[i].yy,0);
					pt[i].yy=Math.min(pt[i].yy,stage.stageHeight);
				}
			}
 
			for (var i in pt)
			{
				pt[i].x = pt[i].xx;
				pt[i].y = pt[i].yy;
			}
			// Lines
			for (var i in joints)
			{
				joints[i].Draw(canvas);
			}
		}
		// ========================================================== //
		private function ptMouse(event:Event):void
		{
			for (var i in mousejoints)
			{
				mousejoints[i].SetMouse( mouseX,mouseY);
				mousejoints[i].Draw(canvas);;
			}
		}
	}
}
 
// ***** [ Particle Class ] ***************************************** //
 
import flash.display.Sprite;
 
internal class Particle extends Sprite
{
	public var old_x:Number;
	public var old_y:Number;
	public var xx:Number;
	public var yy:Number;
 
	// ========================================================== //
	public function Particle(_x:int, _y:int):void
	{
		x = _x;
		y = _y;
 
		xx = _x;
		yy = _y;
 
		old_x = _x;
		old_y = _y;
 
		graphics.lineStyle(1, 0x000000);
		graphics.beginFill(0xFFD22B);
		graphics.drawCircle(0,0,5);
		graphics.endFill();
	}
	// ========================================================== //
}
 
import flash.display.Shape;
 
internal class Joint
{
	public var p1:Particle;
	public var p2:Particle;
	public var len:Number;
 
	// ========================================================== //
	public function Joint(_p1:Particle, _p2:Particle, _len:Number):void
	{
		p1=_p1;
		p2=_p2;
		len=_len;
	}
	// ========================================================== //
 
	public function Draw(canvas:Shape):void
	{
		canvas.graphics.lineStyle(1,0x000000);
		canvas.graphics.moveTo(p1.x, p1.y);
		canvas.graphics.lineTo(p2.x, p2.y);
	}
	// ========================================================== //
 
	public function Apply():void
	{
		var dx:Number;
		var dy:Number;
		var d_len:Number;
		var diff:Number;
 
		dx = p2.xx-p1.xx;
		dy = p2.yy-p1.yy;
		d_len = Math.sqrt(dx*dx + dy*dy);
		diff = (d_len-len)/d_len;
		dx *= 0.5*diff;
		dy *= 0.5*diff;
 
		p2.xx -= dx;
		p2.yy -= dy;
		p1.xx += dx;
		p1.yy += dy;
	}
	// ========================================================== //
}
 
internal class MouseJoint extends Joint
{
	// ========================================================== //
	public function MouseJoint(_p1:Particle, _p2:Particle, _len:Number):void
	{
		super(_p1,_p2,_len);
	}
 
	// ========================================================== //
	override public function Apply():void
	{
			var dx:Number;
			var dy:Number;
			var d_len:Number;
			var diff:Number;
 
			dx = p2.xx-p1.xx;
			dy = p2.yy-p1.yy;
			d_len = Math.sqrt(dx*dx + dy*dy);
			diff = (d_len-len)/d_len;
			dx *= diff;
			dy *= diff;
 
			p2.xx -= dx;
			p2.yy -= dy;
	}
 
	// ========================================================== //
	public function SetMouse(mousex:Number,mousey:Number):void
	{
			p1.x =mousex;
			p1.xx=mousex;
			p1.y =mousey;
			p1.yy=mousey;
	}
	// ========================================================== //
}
 
internal class WeakJoint extends Joint
{
	// ========================================================== //
	public function WeakJoint(_p1:Particle, _p2:Particle, _len:Number):void
	{
		super(_p1,_p2,_len);
	}
 
	// ========================================================== //
	override public function Apply():void
	{
			var dx:Number;
			var dy:Number;
			var d_len:Number;
			var diff:Number;
 
			dx = p2.xx-p1.xx;
			dy = p2.yy-p1.yy;
			d_len = Math.sqrt(dx*dx + dy*dy);
			if(d_len>len){
				diff = (d_len-len)/d_len;
				dx *= diff;
				dy *= diff;
 
				p2.xx -= dx;
				p2.yy -= dy;
				p1.xx += dx;
				p1.yy += dy;
			}
	}
 
	// ========================================================== //
}
 
internal class WeakMouseJoint extends MouseJoint
{
	// ========================================================== //
	public function WeakMouseJoint(_p1:Particle, _p2:Particle, _len:Number):void
	{
		super(_p1,_p2,_len);
	}
 
	// ========================================================== //
	override public function Apply():void
	{
			var dx:Number;
			var dy:Number;
			var d_len:Number;
			var diff:Number;
 
			dx = p2.xx-p1.xx;
			dy = p2.yy-p1.yy;
			d_len = Math.sqrt(dx*dx + dy*dy);
			if(d_len>len)
			{
				diff = (d_len-len)/d_len;
				dx *= diff;
				dy *= diff;
 
				p2.xx -= dx;
				p2.yy -= dy;
			}
		}
 
	// ========================================================== //
}