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Homework Help: Combination of springs

  1. Oct 16, 2006 #1
    I dont understand how to calculate force constants of a combination of springs.

    for example 2 spings parallel with the mass on one end lying on a table.

    or 2 springs attached with mass at one end lying on a table.

    i know that force constant = sum of forces/ extension
    but just dont get how to combine springs!


  2. jcsd
  3. Oct 16, 2006 #2
    Hey Its Easy Man.just Assume The Springs As Resistance And Like We Calculate Net Resistances In Series And In Parallel Calculate The Net Spring Constant.ex-two Springs Of Spring Constant =k Conected In Series Are Equal Ti A Spring Of Constant 2k.the Masses Have Got No Role To Play.only Thing Is That U Have To Find How They Aye Joined In Seriesa Or Parallel.ok...
  4. Oct 16, 2006 #3
    when in Parallel configurations:
    since they are parallel, the extension must be the same.
    k=sum (F) / x
    hence [tex]k=(F_1+F_2)/x = k_1+k_2[/tex]

    when in series configurations:
    when in equilibrium, the tension in the two springs must be equal and the extension is the extension of the first spring + the extension of the second spring:
    k=F/ (x1+x2)
    take the inverse of both side:
  5. Oct 16, 2006 #4


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    Staff Emeritus
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    rohit88 response is incorrect. Please pay attention to the response given by tim_lou, which is the correct answer AND derivation.

    Springs in series behave like resistors in parallel, which springs in parallel behave like resistors in series.

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