i have recreated this simulation here
trying embeding codes
<iframe width="750" height="750" src="https://dl.dropboxusercontent.com/u/44365627/lookangEJSworkspace/export/ejss_model_projectile2cannon/projectile2cannon_Simulation.xhtml" frameborder="0"></iframe>
and thanks a million to Professor Fu-Kwun Hwang for being a great teacher who taught me how to use EJSS to model physics!
read about the answer here
or run by clicking here
or download the model and source codes in the attachments!