Add easing to a rotating 3D object in flash

I imported and image sequence of a 3d model in flash, added a script to rotate the model. Can anyone add to the script below to add easing to the object. I want the object to stop slowly when rotated, instead of an abrupt stop.

photos.stop();

var startX:Number;

var startFrame:int;

var changeDistance:int;

var travelDistance:int;

photos.buttonMode = true;

photos.addEventListener(MouseEvent.MOUSE_DOWN, pressHandler);

function pressHandler(evt:MouseEvent):void {

  startX = photos.mouseX;

  startFrame = photos.currentFrame;

  photos.addEventListener(MouseEvent.MOUSE_MOVE, moveHandler);

  stage.addEventListener(MouseEvent.MOUSE_UP, releaseHandler);

}

function releaseHandler(evt:MouseEvent):void {

  photos.removeEventListener(MouseEvent.MOUSE_MOVE, moveHandler);

  stage.removeEventListener(MouseEvent.MOUSE_UP, releaseHandler);

}

function moveHandler(evt:MouseEvent):void {

  changeDistance = Math.round((photos.mouseX - startX) / +10);

  travelDistance = startFrame + changeDistance;

  if (travelDistance > photos.totalFrames) {

  photos.gotoAndStop(travelDistance % photos.totalFrames);

  } else if (travelDistance < 0) {

  photos.gotoAndStop(photos.totalFrames + (travelDistance % photos.totalFrames));

  } else {

  photos.gotoAndStop(travelDistance);

  }

}