Thanks for the link.<br /><br />3 Re: Circular motion in vertical plane&nbsp; from ahmedelshfie ( [url=http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=1887.0]http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=1887.0[/url] ) is a good one to start with.<br /><br />Most simulations I can view without problem.<br />Some stay black The mentioned one is playing now. I hope it will stay like this.<br />Thanks again<br /><br /><br /><br /><br />	<br />	<br />