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Mike_Egan1-Visitor
1-Visitor
November 18, 2018
Solved

Units are not compatible

  • November 18, 2018
  • 2 replies
  • 4665 views

 

can someone please help.

i have tried everything but i can not get it to calculate.

Keeps saying Units are not compatible

 

2.jpg

 

    Best answer by Mike_Egan

    done, all sorted, thank you all, it helps if I copy things down correctly, brackets and division in the correct place.

     

     

    2 replies

    A
    AlanStevens19-Tanzanite
    19-Tanzanite
    November 19, 2018

    In M3 it looks like you are trying to add 1 (dimensionless) to r^2-b^2 (dimensions of length^2).

     

    Similarly, in M4 you are trying to add dimensionless quantities to dimensional ones.

     

    Alan

      V
      ValeryOchkov24-Ruby IV
      24-Ruby IV
      November 19, 2018

      What is the origin of the formulas?

      May be it is an empirical formulas?

      M
      Mike_Egan1-VisitorAuthor
      1-Visitor
      November 20, 2018

      hi the formulas come from a pressure vessel design code, PD5500

      A
      AlanStevens19-Tanzanite
      19-Tanzanite
      November 20, 2018

      Compare your expressions with those in the design code very carefully.  You will see that you have got some of your division lines in the wrong place!

       

      Alan

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