Editor selections by Topic and Unit

The Physics Front is a free service provided by the AAPT in partnership with the NSF/NSDL.

Computer Program Detail Page

Item Picture
Ejs Free Fall Cartesian Model
written by Wolfgang Christian
This interactive model displays the dynamics of a ball dropped near the surface of Earth onto a table top. The model was designed to extend the free fall concept to include motion in the horizontal direction, allowing students to explore the impulsive normal force that reverses the ball's velocity upon collision with the table. Initial conditions for the ball are an initial positive velocity in the x direction and zero initial velocity in the y direction. The coefficient of restitution for the ball's collision with the platform is less than one.  

This item was created with Easy Java Simulations (EJS), a modeling tool that allows users without formal programming experience to generate computer models and simulations. To run the simulation, simply click the Java Archive file below. To modify or customize the model, See Related Materials for detailed instructions on installing and running the EJS Modeling and Authoring Tool.

Please note that this resource requires at least version 1.5 of Java (JRE).
Editor's Note: The motion of a bouncing ball provides an excellent way to integrate concepts of Law of Conservation of Energy, impulse and momentum, and motion in two dimensions. We recommend introducing this computer modeling activity after students have explored bouncing balls in hands-on activities. SEE RELATED MATERIALS for link to a recommended companion resource.
Subjects Levels Resource Types
Classical Mechanics
- Applications of Newton's Laws
- Motion in Two Dimensions
= Projectile Motion
- High School
- Lower Undergraduate
- Instructional Material
= Activity
= Interactive Simulation
Appropriate Courses Categories Ratings
- Algebra-based Physics
- AP Physics
- Activity
- New teachers
  • Currently 0.0/5

Want to rate this material?
Login here!

Intended Users:
Access Rights:
Free access
© 2008 Wolfgang Christian
Additional information is available.
Easy java Simulations, Ejs, OSP, Open Source Physics, bouncing ball, free fall, gravity, projectile motion, two dimensions
Record Creator:
Metadata instance created June 2, 2008 by Mario Belloni
Record Updated:
June 5, 2014 by Andreu Glasmann
Last Update
when Cataloged:
June 1, 2008
Other Collections:

AAAS Benchmark Alignments (2008 Version)

4. The Physical Setting

4E. Energy Transformations
  • 6-8: 4E/M4. Energy appears in different forms and can be transformed within a system. Motion energy is associated with the speed of an object. Thermal energy is associated with the temperature of an object. Gravitational energy is associated with the height of an object above a reference point. Elastic energy is associated with the stretching or compressing of an elastic object. Chemical energy is associated with the composition of a substance. Electrical energy is associated with an electric current in a circuit. Light energy is associated with the frequency of electromagnetic waves.
  • 9-12: 4E/H9. Many forms of energy can be considered to be either kinetic energy, which is the energy of motion, or potential energy, which depends on the separation between mutually attracting or repelling objects.
4F. Motion
  • 9-12: 4F/H1. The change in motion (direction or speed) of an object is proportional to the applied force and inversely proportional to the mass.
  • 9-12: 4F/H4. Whenever one thing exerts a force on another, an equal amount of force is exerted back on it.

11. Common Themes

11B. Models
  • 6-8: 11B/M1. Models are often used to think about processes that happen too slowly, too quickly, or on too small a scale to observe directly. They are also used for processes that are too vast, too complex, or too dangerous to study.
ComPADRE is beta testing Citation Styles!

Record Link
AIP Format
W. Christian, Computer Program EJS FREE FALL CARTESIAN MODEL, Version 1.0 (2008), WWW Document, (https://www.compadre.org/Repository/document/ServeFile.cfm?ID=7347&DocID=499).
W. Christian, Computer Program EJS FREE FALL CARTESIAN MODEL, Version 1.0 (2008), <https://www.compadre.org/Repository/document/ServeFile.cfm?ID=7347&DocID=499>.
APA Format
Christian, W. (2008). Ejs Free Fall Cartesian Model (Version 1.0) [Computer software]. Retrieved October 22, 2017, from https://www.compadre.org/Repository/document/ServeFile.cfm?ID=7347&DocID=499
Chicago Format
Christian, Wolfgang. "Ejs Free Fall Cartesian Model." Version 1.0. https://www.compadre.org/Repository/document/ServeFile.cfm?ID=7347&DocID=499 (accessed 22 October 2017).
MLA Format
Christian, Wolfgang. Ejs Free Fall Cartesian Model. Vers. 1.0. Computer software. 2008. Java (JRE) 1.5. 22 Oct. 2017 <https://www.compadre.org/Repository/document/ServeFile.cfm?ID=7347&DocID=499>.
BibTeX Export Format
@misc{ Author = "Wolfgang Christian", Title = {Ejs Free Fall Cartesian Model}, Month = {June}, Year = {2008} }
Refer Export Format

%A Wolfgang Christian
%T Ejs Free Fall Cartesian Model
%D June 1, 2008
%U https://www.compadre.org/Repository/document/ServeFile.cfm?ID=7347&DocID=499
%O 1.0
%O application/java

EndNote Export Format

%0 Computer Program
%A Christian, Wolfgang
%D June 1, 2008
%T Ejs Free Fall Cartesian Model
%7 1.0
%8 June 1, 2008
%U https://www.compadre.org/Repository/document/ServeFile.cfm?ID=7347&DocID=499

Disclaimer: ComPADRE offers citation styles as a guide only. We cannot offer interpretations about citations as this is an automated procedure. Please refer to the style manuals in the Citation Source Information area for clarifications.

Citation Source Information

The AIP Style presented is based on information from the AIP Style Manual.

The APA Style presented is based on information from APA Style.org: Electronic References.

The Chicago Style presented is based on information from Examples of Chicago-Style Documentation.

The MLA Style presented is based on information from the MLA FAQ.

This resource is stored in 5 shared folders.

You must login to access shared folders.

Ejs Free Fall Cartesian Model:

Covers the Same Topic As Virtual Laboratory: Potential Energy

This lesson plan from the University of Oregon Virtual Laboratory provides a very structured lab for students to investigate the motion of a bouncing ball, then apply their learning to a simulated situation.

relation by Caroline Hall
Is Based On Easy Java Simulations Modeling and Authoring Tool

The Easy Java Simulations Modeling and Authoring Tool is needed to explore the computational model used in the Ejs Free Fall Cartesian Model.

relation by Caroline Hall

Know of another related resource? Login to relate this resource to it.
Save to my folders



Related Materials

Similar Materials