I do first solution that is i use variable pi=3.14159  in page basic.
And equation:
vx=V*Math.cos(angle*pi/180.);
But i notice that arrow of velocity is down by way strange down more than normally,,cant drag arrow easy for degree i want,,movement of mass slowly.
And if i use less value on slider theta simulation no work.
I don't know what wrong i do.
And i want say another point when i change value of [b]pi[/b] from [b]3.14159[/b] to [b] Math.PI[/b] happend diffrent movement i can say is more good than i use pi=3.14159.
But problems about velocity arrow,,hard control in drag slider of theta and when less value on slider theta simulation no work is the same no change may is have some diffrent in movement become more fast.
I upload applet for you check prof by first value [b]pi=3.14159.[/b]
Applet prof [eye]

/htdocs/ntnujava/ejsuser/37048/users/br/ahmed/airdrag_pkg/airdrag.propertiesFull screen applet or Problem viewing java?Add http://www.phy.ntnu.edu.tw/ to exception site list
Press the Alt key and the left mouse button to drag the applet off the browser and onto the desktop. This work is licensed under a Creative Commons Attribution 2.5 Taiwan License
Download EJS jar file(1431.7kB):double click downloaded file to run it. , Download EJS source (2 times by 2 users) View EJS source
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