a) I basically searched around because it was interesting to me that it was a JAVA applet which illustrated a mathematical analyst of the bouncing of a ball. Other than that I was observing it more and more to figure out what mathematical terms does it relate to.
b) The quality of the content is good because of the graphics and the design of the demonstration of the ball. What caught my attention was the timer or the clock which was used during the demonstration.
c) The effectiveness for teaching is pretty good because the material can be used by an instructor to enrich a lecture or can be assigned to students for individual perusal. It may be used to enhance students' understanding of functions. The height of the bouncing ball, plotted against time, is a series of parabolas. This gives a nice and natural example of a function that analytically must be defined piece-wise.
d) Using this material was easy because the JAVA applet was self-explanatory and easy to follow. Very good tool for graphic functions and can be used in the category of Calculus.