Click on Initialize/Reset to display an overhead view of 2 riders (Red and Blue) on a merry-go-round of radius 10 m.  When you click the Forward button, the MGR will start rotating counterclockwise at constant speed.  At the same instant, Blue will throw a ball toward Red.  The period of the rotation (5 s) of the MGR given at upper right can be changed (see note).  The initial velocity of the ball relative to Blue is 10 m/s at an angle of 0, directly toward Red.  These values can also be changed.  After changing any value, click Reset to initialize the applet to the new parameters. 

The frame of reference from which the motion is observed can be switched (Toggle Frames).  The Inertial Frame is that of, say, a balloonist hovering above the MGR and filming the action.  The Non-Inertial Frame is that of a camera that rotates at the same speed as the MGR.  From this point of view, the MGR does not appear to rotate, and the ball appears to follow a curved path.   (If the applet freezes while toggling frames, try refreshing your browser window.)

We're ignoring any vertical motion of the ball due to gravity.  We could imagine, for example, that the MGR is a large, circular, frictionless platform across which a puck is slid.  It would be like playing air hockey on a circular, rotating table.

Now try the Explorations.

Note:  When running this problem in Netscape, the applet will not function correctly if the period is greater than 5 s.