Post a composite review
Unpost a composite review
Search all MERLOT
Select to go to your profile
Select to go to your workspace
Select to go to your Dashboard Report
Select to go to your Content Builder
Select to log out
Search Terms
Enter username
Enter password
Please give at least one keyword of at least three characters for the search to work with. The more keywords you give, the better the search will work for you.
Select OK to launch help window
Cancel help


Advanced Search


Peer Review

Relative Motion (frame of reference)

by Fu-Kwun Hwang


Overall Numeric Rating:

3 stars
Content Quality: 3 stars
Effectiveness: 3 stars
Ease of Use: 2 stars
Reviewed: May 31, 2005 by Physics
Overview: This is a relative motion applet. The applet has a moving river, with a moving
boat, and a person walking along the ground. The relative speeds of these can
all be changed, and the user can change the frame of reference from which the
motion is viewed. The applet displays either one or two dimensional relative
Type of Material: Java applet interactive simulation.
Recommended Uses: In-class demo or possibly an assignment.
Technical Requirements: Java applet.
Identify Major Learning Goals: Visualize relative motion at constant velocity in one and two dimensions and changes in reference frame.
Target Student Population: Lower-level undergraduate and high school.
Prerequisite Knowledge or Skills: Position, speed, velocity and vectors.

Evaluation and Observation

Content Quality

Rating: 3 stars
Strengths: The applet is complete in that it has a number of moving objects, some
that move in one dimension and some that can move in two-dimensions. The
relative velocities of most of the objects can be controlled. The frame of
reference can be chosen to be any one of the objects. There is an option that
shows the trajectory of an object which can be viewed with respect to several
different reference frames.
Concerns: The graphics are quite simple, and more realistic images could make the applet more understandable. Simple ovals for boats and small circles for water and trees require a bit of imagination. The wrap around of the moving objects also might be confusing for students.

Potential Effectiveness as a Teaching Tool

Rating: 3 stars
Strengths: This can be a very effective tool to show relative motion because of its
flexibility in allowing the user to change reference frames and velocities of
more than two relatively moving objects.
Concerns: The effectiveness may be minimized by the amount of information in the applet and the instructions. A user is going to have to spend some time trying to figure out what is going on, as well as spending time understanding relative motion.

Ease of Use for Both Students and Faculty

Rating: 2 stars
Strengths: The applet allows the user to change reference frames by simply pointing at the
frame of reference.
Concerns: Some of the instructions are a little hard to follow in both the assignment and
the applet itself. It took some time and patience to figure it all out.

Not everything that you see in the applet is explained clearly. The narrow rectangle and object moving on it are not explained. There are also statements in the instructions about making the person cross the river that the reviewers could not make happen.

The 2D option gets confusing since the trajectory path can write over

Other Issues and Comments: Exercises for this applet can be found at