rotate a object z axis

Code :-
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var startingAngle:Number = 45;
var gravity:Number = 0.1;
var currentForce:Number = 0;
arrow.rotationX = startingAngle;
stage.addEventListener(Event.ENTER_FRAME, loop);
function loop(e:Event):void
{
currentForce -= arrow.rotationX / (gravity * 1500);
arrow.rotationX +=  currentForce;
}

Out put :-
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