Eugenia on Rollerblades: Quantitative Observational Experiment


To learn how to determine the speed of the object using ambigous data including assumptions and uncertainties.

Prior Knowledge

Speed of the motion at constant speed

Description of the Experiment

Eugenia skates past the board dropping bean bags every second. Use the data in the video to determine whether she was moving at constant speed or changing speed and if at constant speed, then what the value of the speed was.

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  1. Describe (with words and/or picture) how you can take the data from the video.
  2. What assumptions do you need to make about the bean bags in order to take data?
  3. What is the uncertainty of time measurement? What is the uncertainty of distance measurement
  4. Record Eugenia's position at different clock readings using the experimental uncertainty.
  5. Graph position-verus-time for Eugenia's motion, represent each datum as a rectangle with the sides corresponding to the uncertainties of the measured quantities.
  6. Was Eugenia moving at constanct speed or changing speed? How do you know?
  7. If Eugenia's speed is constant, then what is the value of the speed including the uncertainty of the measurement. How does the size of the bean bag affect your judgment?