Re: Video Analysis

["Paul Zitzewitz" <pzitzewi@sb-f1.umd.umich.edu>]

I have used World-in-Motion (Windows) for two lab activities.  In one 
they plot the motion of a toy airplane moving in a circle (conical 
pendulum) as seen from below.  From the positions they can get the 
velocity and acceleration and do plots of x-y, Vx-Vy, and Ax-Ay as 
well as v-t and a-t.  I captured the video.

The second application is in 2-dim momentum.  I had them find the 
change in momentum when a volleyball was spiked (captured from 
Physics of Sports Videodisk) and test for momentum conservation when 
two cars crashed (Physics of  Car Crashes videodisk).  They could 
also find the change in kinetic energy in the two cases.

I think that the data capture and analysis is sufficiently tedious in 
comparison to sonic rangers that it should be used only when they 
cannot be, i.e. 2-d motion.

Results are mixed.  Students find it very hard to understand what 
they have plotted, especially in the momentum exercises.  I don't 
think that the lab achieved my goal for it, giving students an 
understanding of 2-d momentum conservation.  Of course, the fault 
could easily be my labs rather than the tool used.

Paul

>         This summer I'm having a student look into using video analysis
> tools for our introductory labs and lecture demonstrations.  I would like
> to hear from the folks on this list of their experiences (good and bad)
> with using video analysis tools.  What types of activities have you tried?
> What software have you used (VideoGraph, VideoPoint, etc.)?   Our labs are
> Mac-based, but I'm sure others would be interested in software for IBMs.