Help and FAQ (Frequently Asked Questions)

Free Source Code

The Java source code for the MyPhysicsLab applet is available at www.MyPhysicsLab.com/source/. You should be able to download individual files there by right-clicking on a file. You can also try accessing that directory by anonymous ftp at ftp://www.MyPhysicsLab.com/source/.

The source code is covered by the GNU General Public License. Using the GNU GPL ensures that all subsequent improved versions will be free software. Here free means freedom rather than "no cost".

I would like to hear from anyone downloading, using, or improving the source code. Send me a note about what your interests are with the code. I would also appreciate if you could provide a link to www.myPhysicsLab.com if you use the source code on your website or at your school.

NOTE: the source code that is currently available is for an older version of the applet from 2006. The source code for the current applet is not yet available.

Simplified Source Code

A simplified text-only version of the source code suitable for students to experiment with is available.

Displaying Simulations Off-line

It is possible to display the simulations when not connected to the internet. There are two ways to do this.

1) Run the java applet directly, without a web browser

This method can result in smoother animation, because the java applet gets more computer time than when it is run within a web browser. This method also allows resizing the simulation window.
  1. Establish an ftp connection to ftp://www.myphysicslab.com.
  2. Copy the files that collectively make up the Java applet: Lab.jar, Simulations.jar, Roller.jar, Engine2D.jar.
  3. Run the Java applet by opening (double-clicking) the Lab.jar file. Alternatively try typing at your command line:
    java -jar Lab.jar
    You may need to install the Java Software Development Kit (SDK) in order to run the Java applet in this way.
  4. Choose which simulation you would like to run from the pop-up menu. Resize the window as desired.

2) Download web pages and java applet

If you also want the web pages that go with the applet, you can download a copy of this website onto your computer for display off-line.
  1. Establish an ftp connection to ftp://www.myphysicslab.com.
  2. Copy the files that collectively make up the Java applet: Lab.jar, Simulations.jar, Roller.jar, Engine2D.jar.
  3. Copy the web pages of interest (files ending in .html) and the stylesheet4.css file.
  4. Copy the /images/ and /eqns/ subdirectories if desired. The images are not used by the Java applet, they are only needed for images and equations appearing in .html files.
  5. Open the downloaded web page. If the .jar files and stylesheet are in the same directory as the web page, then the simulation should start running.

This web page was first published November 2001.

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