Yes, I think you really need to see the code in the bouncing ball example. It needs to be unzipped. In Windows right click on its name in Windows Explorer and choose Extract All to make a folder with everything unzipped.
Then, in Eclipse use File/Import from the menu to create a new project from the Existing code. Then you should be able to view the code and run the app to see how it keeps three balls moving at the same time. There's also a clever way to do the slope that avoids calculating the line.
As far as your error goes, you need to look further down in the logcat to see what caused it. From your description it sounds like something in Object2 causes it. It seems like an error in the code, maybe a calculation or nullpointer.
The logcat will usually show (going up from the end) the cleanup after the error, the code that executed before the error, the code that caused the error (usually with a line number in the code), the exception name etc. about the error and a few lines of cleanup from servicing the error. Most errors that cause the app to stop, show this stack dump so you get an idea what happend before, during and after the error.
Hope this helps.