Stopping your bike: Video Analysis with Models in Interactive Physics

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Stopping your bike Video Analysis with Models in
Interactive Physics
A Presentation by Erik Snyder and Tom Koch
Bicycle Project Workshop - Amsterdam - 17-9-99
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• How we spent our time
• Videotaping braking maneuvers.
• Constructing interactive physics model with
  adjustable braking and friction.
• Making our model in interactive physics line up
  with our real life measurements Size of
  bicycle, mass of rider, center of mass of system,
  etc.
• Performing preliminary analyses.

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• Videos of several braking permutations
• front rear brakes - skid/no skid
• rear brake only - skid/no skid
• front brake only - no skid

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Analysis of video
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• Some questions one could ask about the videos
• What are the dimensions of the bike/biker?
• When did the biker begin braking in each video?
• What was the initial speed?
• How long/far did the braking take?
• Which braking techniques were most effective?
• What is the effective coefficient of friction for
  skidding?
• ...

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• If only we had time, we would have
• Annotated our videos frame rate, mass of biker,
  reference meter.
• Developed adaptable instructions for experiments
  to measure such physical properties as
  acceleration, velocity, coefficient of friction
  using our digital videos and programs like
  vidshell.
• Cleaned up the videos and interactive physics
  model.