if(dist < minDist)
       {
        var angle:Number = Math.atan2(dy, dx);
        var tx:Number = ball0.x + dx / dist * minDist;
        var ty:Number = ball0.y + dy / dist * minDist;
        var ax:Number = (tx - ball1.x) * spring;
        var ay:Number = (ty - ball1.y) * spring;
        ball0.vx -= ax;
        ball0.vy -= ay;
        ball1.vx += ax;
        ball1.vy += ay;
       }
      }
     }