If you plot your ball in matlab and update the plots there it will never be exactly as fast as a real life example because you have a plotting processing time. If you know the processing time and just skip some frames you may get a reasonable result although a not so smooth one. A solution is to use the videowriter function which has a framing rate that allows you to exactly calculate the time. An example code adpated from the matlab example:
A = rand(300);
v = VideoWriter('newfile.avi');
The default framerate is 30, so if I have 60 images/plots, the duration of the video will be 2 s. In this way you can exactly calculate how much samples you need and the ration of time needed to end up with a real time plot animation.