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written by Andrew Duffy
The Free Fall Air Resistance model allows the user to examine the motion of an object in free fall, and motion under the effect of air resistance.  This is simply one-dimensional motion (vertical motion) under the influence of gravity.  The blue ball moves under the influence of gravity alone.  The red ball moves under the influence of gravity and air resistance - the strength of the air resistance parameter can be adjusted.

The Free Fall Air Resistance model was created using the Easy Java Simulations (EJS) modeling tool.  It is distributed as a ready-to-run (compiled) Java archive.  Double clicking the ejs_bu_freefall_airresistance.jar file will run the program if Java is installed.

Please note that this resource requires at least version 1.5 of Java (JRE).
View the source code document attached to this resource
  • Free Fall Air Resistance Model Source Code
    The source code zip archive contains an XML representation of the Free Fall Air Resistance model.   Unzip this archive in your EJS workspace to compile and run this model using EJS.
Subjects Levels Resource Types
- Dynamics of Fluids
Motion, Forces, and Energy
- Applications of Newton's Laws
- Motion in One Dimension
= Acceleration
= Gravitational Acceleration
= Position & Displacement
= Velocity
- Lower Undergraduate
- High School
- Middle School
- Instructional Material
= Interactive Simulation
Intended Users Formats Ratings
- Learners
- Educators
- application/java
  • Currently 5.0/5

Rated 5.0 stars by 1 person

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Access Rights: Free access
License: This material is released under a GNU General Public License Version 3 license.
Rights Holder: Andrew Duffy, Boston University
Keywords: Easy Java Simulation, Ejs, acceleration, air resistance, free fall, friction, gravity, position, velocity
Record Cloner: Metadata instance created April 27, 2010 by Mario Belloni
Record Updated: Mar 08, 2016 by wee lookang
Last Update
when Cataloged:
April 16, 2010
Other Collections:


Author: Léo Macena
Posted: June 21, 2016 at 1:04PM
Source: The Open Source Physics collection

Hello Mr. Duffy . I am a college student of Physics in Brazil and I've admired so much your work, in particular , your applet Free Fall Model. I've made ??some big changes in this applet and want to publish it , and I will quote it. May I?
Sorry my poor english, I'm studying recently this language.
Good bye, Mr Duffy.

Léo Macena.

» reply

AAAS Benchmark Alignments (2008 Version)

4. The Physical Setting

4F. Motion
  • 6-8: 4F/M3a. An unbalanced force acting on an object changes its speed or direction of motion, or both.
  • 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/H7. In most familiar situations, frictional forces complicate the description of motion, although the basic principles still apply.
4G. Forces of Nature
  • 3-5: 4G/E1. The earth's gravity pulls any object on or near the earth toward it without touching it.

9. The Mathematical World

9B. Symbolic Relationships
  • 6-8: 9B/M3. Graphs can show a variety of possible relationships between two variables. As one variable increases uniformly, the other may do one of the following: increase or decrease steadily, increase or decrease faster and faster, get closer and closer to some limiting value, reach some intermediate maximum or minimum, alternately increase and decrease, increase or decrease in steps, or do something different from any of these.
  • 9-12: 9B/H4. Tables, graphs, and symbols are alternative ways of representing data and relationships that can be translated from one to another.

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.
  • 6-8: 11B/M2. Mathematical models can be displayed on a computer and then modified to see what happens.
  • 6-8: 11B/M4. Simulations are often useful in modeling events and processes.

Common Core State Standards for Mathematics Alignments

High School — Functions (9-12)

Interpreting Functions (9-12)
  • F-IF.4 For a function that models a relationship between two quantities, interpret key features of graphs and tables in terms of the quantities, and sketch graphs showing key features given a verbal description of the relationship.?
Linear, Quadratic, and Exponential Models? (9-12)
  • F-LE.1.b Recognize situations in which one quantity changes at a constant rate per unit interval relative to another.
  • F-LE.5 Interpret the parameters in a linear or exponential function in terms of a context.
ComPADRE is beta testing Citation Styles!

Record Link
AIP Format
A. Duffy, Computer Program FREE FALL AIR RESISTANCE MODEL (2010), WWW Document, (
A. Duffy, Computer Program FREE FALL AIR RESISTANCE MODEL (2010), <>.
APA Format
Duffy, A. (2010). Free Fall Air Resistance Model [Computer software]. Retrieved October 26, 2016, from
Chicago Format
Duffy, Andrew. "Free Fall Air Resistance Model." (accessed 26 October 2016).
MLA Format
Duffy, Andrew. Free Fall Air Resistance Model. Computer software. 2010. Java (JRE) 1.5. 26 Oct. 2016 <>.
BibTeX Export Format
@misc{ Author = "Andrew Duffy", Title = {Free Fall Air Resistance Model}, Month = {April}, Year = {2010} }
Refer Export Format

%A Andrew Duffy
%T Free Fall Air Resistance Model
%D April 16, 2010
%O application/java

EndNote Export Format

%0 Computer Program
%A Duffy, Andrew
%D April 16, 2010
%T Free Fall Air Resistance Model
%8 April 16, 2010

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 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.

Free Fall Air Resistance Model:

Simulates Physics Classroom: Free Fall and Air Resistance

An editor-recommended interactive tutorial that explores the influence of air resistance on free-falling objects and introduces the concept of terminal velocity.

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 Free Fall Air Resistance Model.

relation by Mario Belloni
Covers the Same Topic As

This editor-recommended interactive tutorial provides content support on factors causing air resistance and how this affects the motion of free fall.

relation by Caroline Hall

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