# The M.U.P.P.E.T. Utilities: Sample Programs

The M.U.P.P.E.T. Utilities manual and disks contain 32 sample programs in both open code and executable form. Students can use these programs as starting points for building programs of their own. In addition, a number of programs have been built as stand-alone programs for students to use without the need for programming.

To download executables of the programs that are available, click on the statement "download program". These programs are DOS programs. (They can be run from Windows, but you will probably need to create a PIF file to do so.) To run them you must also have a "Borland Graphics Interface" (BGI) file appropriate for your graphics screen in the same directory as the program. For most computers today, the appropriate file is "EGAVGA.BGI". Both the program and the BGI file are contained in a "zip" file. Unzip them into the same directory using PKUNZIP or WINUNZIP.

## Sample Programs from The M.U.P.P.E.T. Utilities

These programs are kept as simple as possible so that students may easily work with the code. The interfaces are simple and the programming done in a clear and structured style. Everything extraneous to the physics has been minimized.
• #### Scatter

This program allows you to scatter a beam of classical particles from a localized field of force in two dimensions. This is a good introduction to non-constant forces and prepares the way for understanding how we learn about microscopic systems by scattering. Nine different force fields are provided. Students can try to figure out the shape of the force field from the scattering, width, and velocity dependence of the scattering pattern.

• #### Pendulum

This program solves and displays the motion of a pendulum. Graphs of the angle, angular velocity, and energies (kinetic, potential, and total) are displayed linked in time. One can also view the phase plane and an animation of the motion. Damping and forcing motions can also be set. Parameters can be adjusted and values read off the graphs.

• #### Quantum2

This program allows you to solve the Schroedinger equation in one dimension with one of four different potentials: a square well, a stepped well, a ramped well, and a square well with a work function. This helps students build an understanding of how to read an energy/wavefunction diagram and of how the potential controls the shape of the wavefunction.

• #### Intrfere

This program shows the interference pattern produced by two or more sources of waves. It can be used to study two slit interference or a diffraction grating. In addition to the intensity as a function of angle, the program displays the addition of the phasors that lead to the resultant amplitude.

## Some Programs from the Simulations in Introductory Physics

Simulations in Introductory Physics is a collaboration between Maryland and Sydney Universities to produce useful programs for introductory students. These programs are set up to be used by students as running programs without looking at the code. They have user interfaces which include more explanation and documentation than the M.U.P.P.E.T. programs above.
• #### AirRes1

This program solves for and displays the motion of a projectile thrown straight up under the influence of gravity and air resistance. It allows you to choose a variety of different models to describe the air resistance and allows you to change the parameters of the problem (mass, air resistance coefficient, etc.)

• #### HarmOsc

This program solves and displays the motion of a mass on a spring. Graphs of the position, velocity, and energies (kinetic, potential, and total) are displayed linked in time. One can also view the phase plane and an animation of the motion. Damping and forcing motions can also be set. Parameters can be adjusted and values read off the graphs.

• #### Pulses

This program displays and solves for the motion of up to 50 identical masses connected by identical springs. A pulse is started by moving the first mass up, then down to its starting position.

The program displays an animation of the masses and spring and either

• time graphs of the position and/or velocity of specified masses or
• an animated display of the energy localized in each mass and spring.
The magnitude of the masses on the left and right sides may be set independently.

• #### StWave

This program displays and solves for the motion of up to 50 identical masses connected by identical springs. The masses can be started in a normal mode configuration and allowed to oscillate.

The program displays an animation of the masses and spring and either

• time graphs of the position and/or velocity of specified masses or
• an animated display of the energy localized in each mass and spring.

#### Returns

MUPPET HomePage

The M.U.P.P.E.T. Utilities is available from Physics Academic Software (phone 1-800-955-TASL for information or orders).

Edward F. Redish
Jack M. Wilson
Ian D. Johnston