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Projectile Motion (Galileo and Newton)
written by Todd Timberlake
The EJS Projectile Motion (Galileo and Newton) Model presents two different views of projectile motion. The first view, associated with Galileo, describes projectile motion as a combination of horizontal motion with a constant velocity, equal to the projectile initial horizontal velocity component, and vertical motion with constant acceleration and an initial velocity equal to the projectile's initial vertical velocity component.  The second view, described by Newton in his Principia, presents projectile motion as a combination of inertial motion, with constant velocity equal to the projectile's initial velocity, and motion produced by a constant downward acceleration starting from rest.  These two views are mathematically equivalent, but each view emphasizes different aspects of the motion.

The simulation shows the motion of the projectile for a given initial height, launch speed, and launch angle (all of which can be selected using the simulation controls).  Optionally, the simulation will display the velocity of the projectile, as well as the velocity components (horizontal and vertical for the Galileo view, inertial and forced for the Newton view).  The simulation can also show a series of "ghosts" - images showing the location and velocity of the projectile at regular intervals of time.  Finally, the simulation can display a series of lines that illustrates how the two different types of motion combine to produce the overall trajectory of the projectile.

By default the view is scaled to fit the entire trajectory, as well as any ghosts, within the window.  This generally means that the horizontal and vertical distances are not shown to the same scale, which can lead to distortions in the shape of the projectile and other similar effects.  The user has the option to square the display (see below) to remove these effects, although this may result in the visual elements occupying only a small portion of the viewing window.

Please note that this resource requires at least version 1.5 of Java (JRE).
1 source code document is available
Subjects Levels Resource Types
Classical Mechanics
- Gravity
- Motion in Two Dimensions
= Projectile Motion
- Newton's First Law
= Inertia in Motion
- Newton's Second Law
= Force, Acceleration
- Lower Undergraduate
- Middle School
- High School
- Instructional Material
= Interactive Simulation
Intended Users Formats Ratings
- Learners
- Educators
- General Publics
- application/java
  • Currently 0.0/5

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Access Rights:
Free access
This material is released under a GNU General Public License Version 3 license.
Rights Holder:
Todd Timberlake
EJS, Easy Java Simulations, Galileo, Newton, OSP, Open Source Physics, free fall, gravity, inertia, projectile
Record Cloner:
Metadata instance created July 3, 2012 by Todd Timberlake
Record Updated:
June 11, 2014 by Andreu Glasmann
Last Update
when Cataloged:
July 3, 2012
Other Collections:

ComPADRE is beta testing Citation Styles!

Record Link
AIP Format
T. Timberlake, Computer Program PROJECTILE MOTION (GALILEO AND NEWTON), Version 1.0 (2012), WWW Document, (
T. Timberlake, Computer Program PROJECTILE MOTION (GALILEO AND NEWTON), Version 1.0 (2012), <>.
APA Format
Timberlake, T. (2012). Projectile Motion (Galileo and Newton) (Version 1.0) [Computer software]. Retrieved May 26, 2017, from
Chicago Format
Timberlake, Todd. "Projectile Motion (Galileo and Newton)." Version 1.0. (accessed 26 May 2017).
MLA Format
Timberlake, Todd. Projectile Motion (Galileo and Newton). Vers. 1.0. Computer software. 2012. Java (JRE) 1.5. 26 May 2017 <>.
BibTeX Export Format
@misc{ Author = "Todd Timberlake", Title = {Projectile Motion (Galileo and Newton)}, Month = {July}, Year = {2012} }
Refer Export Format

%A Todd Timberlake
%T Projectile Motion (Galileo and Newton)
%D July 3, 2012
%O 1.0
%O application/java

EndNote Export Format

%0 Computer Program
%A Timberlake, Todd
%D July 3, 2012
%T Projectile Motion (Galileo and Newton)
%7 1.0
%8 July 3, 2012

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Citation Source Information

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

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Projectile Motion (Galileo and Newton):

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 Projectile Motion (Galileo and Newton).

relation by Wolfgang Christian

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