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Help with simple conversion

  • 23-01-2015 08:52PM
    #1
    Shamrocks320
    Registered Users, Registered Users 2 Posts: 17 ✭


    Could somebody kindly show me the solution for this: (I am trying to convert quantities)

    Convert 14 stokes into m(2)/s.

    I know the conversion factor is 1 x 10(4) so it should be a case of dividing 14 by 1 x 10(4) to get 1.4 x 10(-3) m(2)/s

    I do not know how to input this into the calculator to get the above answer I took from back page of book.

    Could someone show me the solution please and thank you. In other words, how you would work it out with pencil and paper.

    Thanks a ton(UK)

    My math is very basic so that is why I am asking here!


Comments

  • #2
    TimeToShine
    Registered Users, Registered Users 2 Posts: 4,880 ✭✭✭TimeToShine


    1 m(2)/s is 10000 stokes.

    x m(2)/s is 14 stokes.

    Cross multiplying, you get 10000x = 14 so x is 1.4/10000 m(2)/s which is the answer you posted. Look up the cross multiplication method - it works for conversion questions like these, is simple, systematic and requires next to no prerequisite knowledge. You pretty much did it out in the OP anyway!


  • #3
    TheBody
    Registered Users, Registered Users 2 Posts: 5,657 ✭✭✭TheBody


    You are using scientific notation here. In particular, the rule for division is:

    [latex]\frac{a\times 10^p}{b\times 10^q}=\frac{a}{b}\times 10^{p-q}[/latex].

    In your case:

    [latex]\frac{14}{1\times 10^4}=\frac{1.4\times10^1}{1\times 10^4} =1.4\times10^{-3}[/latex]

    Notice how the "number bits" were divided while the powers on the 10 were subtracted.


  • #4
    MathsManiac
    Registered Users, Registered Users 2 Posts: 1,595 ✭✭✭MathsManiac


    You also asked about doing it on the calculator.

    Most scientific calculators have a button for "...times 10 to the power of..." and it usually has either "exp" or "EE" on it.

    So, on my calculator, I would do this calculation as:

    14 [divided by] 1 [exp] 4 [=]

    ...and I get 0.0014.

    There should be another button to use when you want the calculator to display your answers in scientific notation. It might say [FSE], but different calculators are different. IF you do have an FSE button, it cycles the display through "floating point", "scientific" and "engineering" notation.
    • Floating point is ordinary notation.
    • Scientific is the notation you've been using in this question: (a number between 1 and 10) X (10 to the power of something).
    • Engineering is (a number between 1 and 10000) X (10 to the power of a multiple of 3).


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