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Re: [Phys-L] Simon Biles Triple Double in Slow Motion

Although "complicated" there are several physics principles that can be demonstrated.

1. An object in the earth's gravitational field falls with an acceleration of 9.8 m/s each second

2. An airborne object's horizontal velocity (assuming horizontal velocity is slow enough for drag to be negligible)  doesn't change doesn't change significantly.

3. The resulting center of mass motion in 2 dimensions is a parabola.

4. Getting good results requires thoughtful placement of the camera. Not so thoughtful placements can lead into discussions of why 1, 2 and/or 3 do not appear to be valid.

5. Motion analysis from videos require some skill in making assumptions. E.g. where is Simone's c.o.m.? For a typical person their center of mass would be approximately at their belly button. But Simone is really muscular so may be atypical. A good question would be to ask "Can one verify Simone's center of mass using information from the video?" Perhaps this is bootstrapping? Again another lead in to better understanding of how to solve problems by making and verifying assumptions.

Although there are better ways to analyze human motions camera views are not really so terrible to analyze. There is free motion tracker software. I believe Vernier and Pasco , and perhaps others provide analysis software in their offerings. The one caveat I have is motion analysis generally takes considerable time and some experience. Start with simple things and work up to more difficult motions.  Such analysis is a good skill builder but best learned incrementally.


On 6/12/2021 12:00 PM, wrote:
Date: Fri, 11 Jun 2021 17:57:44 +0000
From: "Marx, David" <>
To: "" <>
Subject: [Phys-L] Simon Biles Triple Double in Slow Motion

Content-Type: text/plain; charset="us-ascii"

This is wonderful. Anyone care to comment on the Physics and whether this clip would be useful in teaching physics?

Take care, David