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Homework Help: Error propagation

  1. Jan 28, 2015 #1
    1. The problem statement, all variables and given/known data
    suppose i measure the time t for 20 oscillations fro a pendulum. the period is T.

    2. Relevant equations
    Since T = t / 20
    delta T = delta t right?

    3. The attempt at a solution
    since the 20 is a numerical value, it does not come in the error propagation, does not? when i used the above equation, i can't get the required answer but when i divide by 20, the answer is obtained.

    can someone explain why?
  2. jcsd
  3. Jan 28, 2015 #2


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    Homework Helper

    T is what you measure the period to be, right? (T = t / 20) So the true period will be T+ΔT where ΔT is some error.

    The true time it takes for 20 oscillations is 20(T+ΔT), which equals the time you measured plus some error Δt


    So if [itex]20T=t[/itex] then:

    [itex]20ΔT=Δt[/itex] ... or ... [itex]ΔT=\frac{Δt}{20}[/itex]
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