title: iOS: Simple Physics for a UIView
body: <p>I have a <code>UIView</code> that a user drags around via setting its center in the <code>touchesMoved:</code> method.  When the user lets go, I want the <code>UIView</code> to fall off the screen according to how fast and what direction they were moving it in.</p>
  
  <p>Do I need to somehow create a vector by comparing the <code>UIView</code>'s last center point to it's new center point? And subtract a fixed amount to the vector's y value every so often with a <code>NSTimer</code>?</p>