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Uncertainty calculation

  1. May 1, 2015 #1
    1. The problem statement, all variables and given/known data
    My homework question says: the uncertainty in length 1 is +/- 0.1 and in length 2 is +/- 0.1 : calculate the percentage uncertainty in V where V

    L1-L2 is 30

    2. Relevant equations

    V= (1/(L1-L2))^0.5 where L is the length

    3. The attempt at a solution

    So what I did was add the two uncertainties to get +/- 0.2
    I then worked out percentage uncertainty by doing 0.2/30 *100%

    and then I multiplied my answer by 0.5 since it is being square rooted.

    Is this correct or have I made a mistake somewhere in my method?
  2. jcsd
  3. May 1, 2015 #2


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    If you have learned to add uncertainties linearly, then: yes (correct) and no (no mistake) :smile:
  4. May 1, 2015 #3
    thanks :)
  5. May 1, 2015 #4


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    Your welcome, but mind you: it's an opinion: there's no guarantee

    And: If the uncertainty in L1 - L2 is 0.2, why isn't this difference written as 30.0 ?
  6. May 1, 2015 #5
    don't know what your talking about sorry
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