You'd think so. I had problems with it updating while the ball was technically in the floor. I had it detect when it hit the floor by when it passed the frame (obviously) but then it would switch the vector and update the position but the resulting position was still under the floor and it would do it again. So the ball would bounce like 4 times then get stuck in the floor.

<script type="text/javascript">alert("remember when scripting attacks worked?");</script>