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Homework Help: Scientic error expected in displacement vs time graph and velocity vs time graph

  1. Sep 17, 2011 #1
    Scientific error expected in displacement vs time graph and velocity vs time graph

    1. The problem statement, all variables and given/known data

    When I used a sensor to measure my movements of walking, during the graph of displacement vs time, I received a slope of -0.742 meters/second, and on the velocity vs time graph the mean I received -0.2774 meters/second.

    Do you consider these values to be the same within experimental error? Is this what is scientifically expected? Explain why or why not.

    I answered yes, but I don't know why. Is it because I didn't walk in a perfectly straight line or is it because I moved my body to the extent that the wavelengths from the sensor hit me too early/late? Thanks.

    2. Relevant equations

    3. The attempt at a solution
    Last edited: Sep 17, 2011
  2. jcsd
  3. Sep 17, 2011 #2
    To calculate error you usually need to do a large number of tests then calculate the mean then the mean deviation

    [itex]\sum \frac{v_{i}}{N}\equiv \overline{v}[/itex] i to N for the mean

    [itex]\sum \frac{\sqrt{(\overline{v} -v_{i})^{2}}}{N}[/itex] for the mean deviation

    if your mean + or - your mean deviation includes your sensor measurement it would be with in experimental error, if not you'd need to explain the systematic errors that occurred or the possible random errors

    edit* I'm assuming this is for a lab?
  4. Sep 17, 2011 #3
    Yes, its for lab.

    Thanks. I'm going to stick with inaccuracies with with walking perfectly straight then as the main problem because I can't imagine the wavelengths being able to bounce off me without myself moving slightly out of place. I could mention there could be a minor systematic error with the sensor measuring slightly inaccurate.
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