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Best answer by Werner_E
@JLand0299 wrote:

I was just told by my instructor that this particular problem can not be done in MathCad. Due to the fact that the actual unit for C_l and C_s needs to be Btu/ (lbm*F) or something like that. He just told me to add values without units for just a numerical answer. I do see where I need to add the multiplication to the formula. 

 

I am pretty sure that this problem CAN be done in Mathcad and even in Prime. You just have to use Delta °F instead of just °F. Temperature units are a bit tricky - if you want to be on the simple and safe side you may consider using K throughout.

But there still is a unit mismatch in the first summand - there's missing lb or lbm in the denominator.

I added it the bold way in the following screenshot but you'll have to check the formula or the units assigned:

B.png

 

1 reply

W
Werner_E25-Diamond I
25-Diamond I
October 7, 2018

Can't you see that every of your three summands has different units? You simply can't add quantities of different dimensions!

Furthermore you are missing a multiplication sign between C.l and the parenthesis. Without that multiplication sign Prime assumes a function C.l with T.p-T-m as argument.

B.png

 

    J
    JLand02991-VisitorAuthor
    1-Visitor
    October 7, 2018

    I was just told by my instructor that this particular problem can not be done in MathCad. Due to the fact that the actual unit for C_l and C_s needs to be Btu/ (lbm*F) or something like that. He just told me to add values without units for just a numerical answer. I do see where I need to add the multiplication to the formula. 

    Screenshot (361)_LI.jpg

    W
    Werner_E25-Diamond IAnswer
    25-Diamond I
    October 8, 2018
    @JLand0299 wrote:

    I was just told by my instructor that this particular problem can not be done in MathCad. Due to the fact that the actual unit for C_l and C_s needs to be Btu/ (lbm*F) or something like that. He just told me to add values without units for just a numerical answer. I do see where I need to add the multiplication to the formula. 

     

    I am pretty sure that this problem CAN be done in Mathcad and even in Prime. You just have to use Delta °F instead of just °F. Temperature units are a bit tricky - if you want to be on the simple and safe side you may consider using K throughout.

    But there still is a unit mismatch in the first summand - there's missing lb or lbm in the denominator.

    I added it the bold way in the following screenshot but you'll have to check the formula or the units assigned:

    B.png

     

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