# Physics Learned Wrong!?

**URL:** <https://forum.kirupa.com/t/physics-learned-wrong/313975>\
**Category:** flash\
**Created:** [September 15, 2010, 8:48am UTC](https://forum.kirupa.com/t/physics-learned-wrong/313975 "2010-09-15T08:48:33Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![Rifts1103](https://avatars.discourse-cdn.com/v4/letter/r/7993a0/32.png) [@Rifts1103](https://forum.kirupa.com/u/Rifts1103)\
**Post date:** [September 15, 2010, 8:48am UTC](https://forum.kirupa.com/t/physics-learned-wrong/313975/1 "2010-09-15T08:48:33Z")

</div>

Hey in school I always learned this

```auto

                    +y 
                     |
                     | 
                     |
       -x <------------------ +x
                     |
                     | 
                     |
                    -y

```

so can someone please explain to me why in flash the Y is flipped?

I have a code which is very simple moved my movieclip left, right, up, down with arrow keys.

here is the actual movement part

```php

// move every frame
function moveMascot(event:Event) {
	var speed:Number = 5;
	
	if (leftArrow) {
		mascot.x -= speed;
	}
	if (rightArrow) {
		mascot.x += speed;
	}
	if (upArrow) {
		mascot.y -= speed;
	}
	if (downArrow) {
		mascot.y += speed;
	}

```

now shouldn’t uparrow be += and downarrow be -=??

Thanks