Catch the ball in the air to observe 
    conservation of momentum!





   Controls:
 
	   jump  = space 
	   left  = j
	   right = k



    Troubleshooting: 
    Remember to keep the mouse pointer over the white square.	
    Clicking once stops the action, click again to continue.    
    If keyboard does not respond, double-click on the applet.


Here are the two source files CS217.java and Player.java with lots of comments.
One can easily substitute another player.