This paper describes the use of open source video analysis software in the study of the relationship between the velocity of falling objects and time. We discuss an experiment in which a steel sphere falls in a container filled with two immiscible liquids. The motion is similar to that of a skydiver falling through air.

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Tracker is a video analysis package (running Windows) built on the Open Source Physics (OSP) Java framework. It is designed to be used in introductory college physics labs and lectures; http://www.cabrillo.
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