title: Animation with changing speed
body: <p><strong>hello,</strong>
  I develop an application in c# and WPF that calculate the time of free fall object. The object represented by ellipse and show the proccess of the object on screen. The application get from the user the initial height, initial speed and the dirction(up or down) of the object. The application calculate by formula the max height of object and current height of object by time (I appand a stopwatch).
  I wanted to draw the ellipse every time by the  Canvas.setBotton property. The problem is the ellipse doesn't animated clear. The ellipse "move" in step and doesn't smooth (the move doesn't continuous).
  The speed of ellipse change every milisecond, hence I can't use animation of WPF (I use formula that know where exactly the ellipse located). Somebody know what to do? Thank's </p>