title: Pendulum with moving pivot
body: <p>I'm making a game which you can see here, if you are on Windows or Linux: <a href="http://insertnamehere.org/birdsofprey/" rel="nofollow noreferrer">http://insertnamehere.org/birdsofprey/</a></p>
  
  <p>If you click and hold your mouse on a bird, you can see I'm just swinging the bird back and forth in pendulum motion. I would like to, instead, implement a more realistic motion, where the movement of your mouse affects the swinging of the bird like a pendulum with a moving pivot.</p>
  
  <p>I found <a href="http://www.maplesoft.com/applications/view.aspx?SID=4888&amp;view=html" rel="nofollow noreferrer">a document</a> on this topic but the equations rely on knowing the pivot's acceleration (X'' and Y''), which I do not; I am only repeatedly translating the bird graphic to the current mouse position.</p>
  
  <p>I have the bird's angle (-180 to 180 degrees), angular velocity and acceleration. I will need to alter these three variables each time the mouse is moved, so I will also have the last (x,y) and the new mouse (x,y).</p>
  
  <p>Is this enough to make a good simulation of a pendulum with moving pivot?</p>