Learning Exercise

Newtons's Laws Physlet Problem #1

Adaptation of a Physlet problem to work as a calculated question within WebCT.
Course: Introductory Physics

Educational physics applets designed to be scripted in JavaScript for use in quizzes, homework problems, and Just in... see more


The orgininal problem may be viewed at
A light block slides on top of a heavy block on a frictionless surface. An external force is applied to the light block, and friction causes the heavy block to accelerate.

The modification utilizes the random parameter feature of the WebCT
calculated question format. The advantage here is that you can allow unlimited
attempts and encourage collaboration. Since the parameters are
re-randomized on each attempt, it is appropriate to report the correct answer after an incorrect submission.

The WebCT version of this question is at

Download and unzip the file, and import into WebCT. A question database
category will be created called physlet_problems (if it does not already

There are two parts to this problem. Part a asks for the coefficient of friction, and part b asks for the external force. Since WebCT does not provide a way to extend a given set of parameters over mulitple questions, the motion in part b is reversed.

Once you have the problem working, create a quiz that uses it. The quiz
settings that I find most effective for this problem are

  • Unlimited attempts

  • Highest score determines grade

  • Release the score once the quiz has been submitted

  • Show the student's response for each question

  • Show the correct answer for each question

Send questions to

Technical Notes

This question looks for the java archive files in the webct_install_dirwebctuserclasses subdirectory (i.e.,


Newton's Laws