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Questions on an end of the year project

  1. May 8, 2016 #1
    1. The problem statement, all variables and given/known data
    Hey guys.
    I am attempting to do an end of the year physics project on gears on bikes and bike ratios. For the presentation I want to explain how gear ratios and the like work and demonstrate a homemade gear. I also need to have and experiment to go along with it. My basic plan is to ride my bike up a short section of hill and measure the number of pedal rotations as well as possibly speed and calories for efficiency? I need some help coming up with variables to measure for my experiment and I am lost! Can you guys help?

    2. Relevant equations

    3. The attempt at a solution
  2. jcsd
  3. May 8, 2016 #2


    Staff: Mentor

    Many times, scientists will measure everything they can. They don't just select a few variables and then later realize there was something else they should have collected.

    GIven that what things can you measure as you perform your experiments?
  4. May 8, 2016 #3

    Okay. Let me rephrase my question then. What sort of equations and graphs could I design surrounding gear ratios and bicycle movement up a hill in different gears? Would rotational velocity be appropriate? How about torque?
  5. May 8, 2016 #4


    Staff: Mentor

    Isn't that part of your project to come up with various charts and to then show which ones are relevant and why?

    THere are many articles on google about bike gear ratios and mechanical advantage that you could research and factor in. From there you could decide what to plot. For starters, you could measure progress up the hill each second by video taping the experiment and you could get the pedal rotations, wheel rotations and rider effort if they slow down or speed up during the take.
  6. May 8, 2016 #5
    Okay great! Thanks for helping me with some of the ideas. You don't this this project is crazy right? I'm just feeling a little lost and the things you said sounded like they were on the right track for me. Is there anyway you think I could measure efficiency from this experiment? (calories burned or something?) Or would that be over doing it and getting on the wrong track?
    Thanks so much I really appreciate your ideas.
  7. May 9, 2016 #6


    Staff: Mentor

    No the project isn't too crazy. I did one where I measured the flight of a frisbee using some video analysis and tried to model it in Java. I remember placing a measured piece of rope down so that I could get distance measurements as I watched the video. I've seen a similar construct in a NOVA show on the bouncing bomb of WW2 where they built a grid of string in front of the camera and took measurements as the plane dropped the spinning bomb to see how it skipped on the water.

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