[quote author=Fu-Kwun Hwang link=topic=34.msg8004#msg8004 date=1301214298]
Here is the EJS version of the same applet

[/quote]

dear prof!
i solved a bug
please replace the following line in the code.

// yfun2="("+yfun+")/vdiv+v0";
yfun2="("+yfun+")/vdiv*dy+v0";

missing dy :)
thanks again for advancing the world of physics education.