Interactive Physics is more like a tool than a textbook. It’s the spreadsheet program of the Newtonian-mechanics world. With it, you can set up physical situations and see “what if?” scenarios, just as you would with a financial model in Excel or Wingz.
To let you do this, Interactive Physics provides a set of tools in a familiar tool palette for drawing simple two-dimensional objects (masses) and interconnecting them with massless strings, springs, or dampers. You can also apply constant forces and set such conditions as gravity, air friction, elasticity of objects, densities. and surface friction. Any object can be rotated and/or anchored to the screen so that it becomes an immovable object during the simulation. Once your setup is complete, you simply click on the Run button and watch what happens. The objects move on-screen just as they would if you had set them up on a table in front of you (and you can even witness impossible simulations that require perfect vacuums, frictionless surfaces, and the ability to turn gravity off).
With all these calculations to complete, the program is no speed-burner on a Mac Plus. Knowledge Revolution has recognized this problem, though, and provided a simple and elegant solution: a “tape player” that records screens from the simulation into memory. When you've gone as far as you want (or reached a memory limit), you can stop the simulation and play back the recorded frames at a user-selectable rate.
If that’s all there were to Interactive Physics, it would still stand above the rest, but Knowledge Revolution has added the ability to monitor objects as they move and bounce. Every object can have its own set of vectors and meters that displays an amazing variety of data. Vectors display magnitude and direction of velocity, acceleration, and a variety of forces (with x-y components if desired). Meters—for everything from velocity to surface friction—are even more extensive. They can display their data as numbers or analog meters, or on a short strip-chart recorder that runs during the simulation.
Interactive Physics is also able to display multiflash strobelike images. All you need to do is select the number of simulation steps between “flashes,” and the moving objects leave trails of themselves behind.
Interactive Physics comes with a well-written 103-page manual that is indexed and includes tutorials, reference sections, and technical information. An additional disk provides more than 50 well-organized demonstrations and experiments that are representative of those found in a good physics book.
PHYSICAL LIMITS The program is not without its limitations. For example, you can have only ten masses on the screen and they can be connected with a maximum of five strings, springs, or dampers. Furthermore, you can apply a maximum of only ten forces to objects, not including gravity.
Output is limited. You can't print screens unless you do a screen capture. And I'd like to be able to export my “tape memory” to animation programs such as VideoWorks and send my data to a spreadsheet. Masses can't overlap, so the only way to “pin” one object to another is with a string or spring. It would be nice to have multiple layers of objects that could be overlapped and fixed to each other with a pivot. Another limitation is the stick-figure quality of the graphics.
The program is as crash-free as any version 1.0 I've used. It does, however, contain a nonfatal error that sometimes causes the meters to deliver erroneous readings. Knowledge Revolution knows of the bug and has promised a fix.
THE BOTTOM LINE Interactive Physics isn’t cheap. Most universities and school districts may be able to afford it, but it’s too expensive for most individual teachers or students.
But if you’ve got the budget, when students ask those hard questions, you can answer them by doing. It's a physics teacher's dream come true.
Hipschman, Ron. (April 1990). Interactive Physics. MacUser. (pg. 65).
Knowledge Revolution
Applications
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2021-11-28 / 
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Interactive_Physics.sit_.hqx
Emulating this? It could probably run under: 
Mini vMac
