Note: The following information is also found in the preface of Physlet Physics.
Browser Tests and System Requirements
Browser Tests
Physlet Physics provides physics teachers with a collection of ready-to-run, interactive, computer-based curricular material spanning the entire introductory physics curriculum. All that is required is the Physlet Physics CD and a browser that supports Java applets and JavaScript to Java communication. This combination is available for recent versions of Microsoft Windows and most versions of Unix. Although we occasionally check Physlets using other combinations, Microsoft Windows 2000 and Windows XP with both IE and the new Open Source Mozilla browser are our reference platforms.9
To check whether your computer already has Java installed, go to the Preface Chapter on the CD and navigate to the Browser Tests and System Requirements page. There you will find two buttons.
Figure I.4.1: The “Check for Java” and Platform Check” buttons.
Click the buttons to check for Java and your computer platform. If your browser fails the Java test, please continue reading for information on getting and installing Java.
Microsoft Java
Most, but not all, versions of Windows include the Microsoft Java Virtual Machine (JVM). To
test if any version of this JVM is installed on your computer, type the jview command at a DOS
prompt. If a program runs, you have a Microsoft JVM. If you receive an error that no program by that name exists, you don’t.
The Microsoft JVM is installed and updated on your computer with Windows Update. Previously it could be downloaded separately, but now Microsoft only uses Windows Update. The main Web
page from Microsoft about Java is http://www.microsoft.com/java.
Sun Microsystems Java
The Sun JVM is downloadable from the Java website: http://java.sun.com. After downloading
the file to your hard drive, double-click on its icon to run the installer. Follow the instructions the installer provides.
9 Physlets have been tested on Linux and various versions of Unix. The only major operating system
vendor that does not support Physlets is Apple Computer since the standard Macintosh and Power PC browsers do not support JavaScript to Java communication.
You can check your computer for a properly installed Sun JVM and change its properties by clicking on the Java plug-in icon in the Windows Control Panel.
Figure I.4.2: The Control Panel folder showing the Java plug-in icon.
The following dialog box will appear:
Figure I.4.3: The Java plug-in dialog box is accessed from the Windows Control Panel.
Although it is possible to simultaneously install Java VMs from Microsoft and Sun Microsystems on Windows computers, a browser can only run one VM at a time. You can switch between these two JVMs in Internet Explorer. Start IE and click the Advanced tab under Tool|Internet Options from the IE menu bar. The following dialog box shown in Figure 4 will appear.
Figure I.4.4: The advanced Internet Options dialog box is accessed from within Internet Explorer.
Figure 4 shows that this computer that has two Java VMs and that it is currently configured to run the Microsoft VM. The option for the Java (Sun) VM will not appear unless the Sun Java Run- Time Environment has been installed. You will need to close all browser windows if you decide to switch VMs. You do not, however, need to restart the computer.
Non-Microsoft Browsers
Netscape, Opera, and Mozilla offer alternatives to the Microsoft Internet Explorer on Windows operating systems. You can download this browser from the Mozilla website:
http://www.mozilla.org.
After downloading the file to your hard drive, double-click on its icon to run the installer. Follow the instructions the installer provides. The Mozilla browser requires that the Sun JVM be installed on your computer.
Chapter I-5: Mechanics
The mechanics chapters represent the starting point for a study of physics. The Illustrations in these chapters tend to focus on introducing topics and provide an
interactive alternative to the standard textbook treatment. As we discuss below, you will find these chapters to be particularly rich in multiple representations of concepts as motion graphs, energy-bar graphs, and mathematical modeling are integrated throughout.
What Is Covered?
• All mechanics topics typically covered in an introductory course are found in the mechanics chapters of Physlet Physics.
• Chapter 1 provides an introduction to Physlets and Physlet-based exercises and is designed to get students through some of the difficulties they may encounter as they embark into unfamiliar territory.
• Reference frames and relative motion are in a separate chapter, Chapter 9.
• The first Newton’s laws chapter (Chapter 4) deals with the basic concept of force, free-body diagrams and the forces of weight, tension, and normal force. The Newton’s Laws II chapter (Chapter 5) goes beyond Chapter Four to include friction (including air friction), circular motion, and springs.
• The Rotations about a Fixed Axis chapter (Chapter 10) introduces the concepts associated with rotation: angular variables, torqure, angular momentum and the angular momentum of particles. General Rotations (Chapter 11) extends this to objects that rotate and translate thereby including rolling and collisions between an object in translational motion with a rotating object (e.g. mass dropped on a rotating merry-go-round).