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Homework Help: Finding how weight placed on a ruler affects its oscillation.

  1. Feb 28, 2010 #1
    1. The problem statement, all variables and given/known data
    I'm currently having a bit of trouble figuring out how to most effectively execute my experiment. It's somewhat practical; I need to find how the masses placed on the end of a vibrating ruler will affect its oscillation.

    I know that the ruler is a standard 12 inch (30.5 cm) ruler, with 20 centimeters hanging off the edge of a desk, and that I have several weights for my use (weights range from 5g-50g)

    2. Relevant equations

    I have no idea.

    3. The attempt at a solution

    My idea was to simply tape the weights to the end of the ruler using lightweight scotch tape, and bending the ruler down approximately 1-2 inches from its equilibrium position, and timing how long it takes for the ruler to reach its equilibrium position at 4 or 5 different weights. Is this the most accurate way to determine how weights affects time of oscillation?
  2. jcsd
  3. Feb 28, 2010 #2


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    Homework Helper

    I suspect the motion will go like this Wikipedia graph for damped harmonic motion: 200px-Step_response_for_two-pole_feedback_amplifier.PNG
    The measurement you suggest would be the time for the oscillations to die out.

    I think it would be more interesting to measure the frequency or period of the oscillations within the overall exponential decay damping curve (dashed line). Unfortunately I can't think of an easy way to measure those. Have you got a digital camera with a video mode - if so, you may be able to video it along with a stopwatch and then watch in slow motion to see the period or count the number of oscillations in a measured time.
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