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Homework Help: Pendulum Problems

  1. May 7, 2014 #1
    1. The problem statement, all variables and given/known data

    Estimate your walking speed assuming that your legs are ideal PHYSICAL PENDULA.

    Estimate your walking speed by measuring how long it takes you to walk 10 m.

    Was your "pendulum" walking speed faster of slower than your "clocked" walking speed? Why?

    2. Relevant equations

    3. The attempt at a solution

    I'm unsure of how to calculate the first question. I'm going to assume that I take a step every half second but I don't know where to start from that assumption.
  2. jcsd
  3. May 7, 2014 #2


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    Staff: Mentor

    You'll need some additional assumption on the step size, otherwise it does not work. I don't like the problem statement, it should make that clear (or suggest a value).
  4. May 7, 2014 #3


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    Gold Member

    True, but that's fairly easy to measure. The hard part is estimating effective pendulum length.

    (This question reminds me of a Christmas lecture series from the Royal institution many decades ago which looked at the effects of scale on living things. The lecturer demonstrated that, for the same basic body plan, all animals run at the same speed, but larger animals walk faster, as √L. As a result, sufficiently small animals hardly ever walk.)
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