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Newbie question......I put in degree units and the thing breaks

BillMcEachern
1-Newbie

Newbie question......I put in degree units and the thing breaks

Hi,

I don't use Mathcad all that much anymore so I am no longer very skilled at it. This is also my first post to this forum.

I defined a range variable with no units and then used it to compute some normal force numbers. I then put in the unit simple in the range variable for degrees and the thin stopped working int the force formula. Can anyone shed some light on this one for me? I have attached images of the area of the sheet that is giving me grief. I can just do it all in radians and it works fine.......just figured I would see what I am missing here.

6 REPLIES 6

Hi William,

You have raised an expression involving units to a power involving a range variable or a vector. As a result, there is no way to determine the dimensions of the result. If an expression is defined with units, you can raise it only to a fixed real power.

Hope this can help.

/K

I think you read it wrong but thanks.

If you define a range variable with units you need to include the second term. Try a:=0*deg,1*deg...45*deg

Thanks. That did the trick.

You could use define a vector instead of using a range variable.

See attached image.

Mike

Whether the argument to sin(x) is default radian or °, the result is a number or a range of numbers, dimensionless numbers ... as well as x*sin(x). If you put units ° , you just have to scale it again vs the default radian, but still dimensionless numbers [a range of numbers], in other words a dimensionless scaling function. Assume you do that part right and get the desired function, you are left with A [unit of something] and q [unit of something]. Their product are now in the corresponding unit system of the measured or entered A, q. The coefficient C is dimensionless , therefore you only need to put units in A & q. What you don't say is what alpha represents [ orientation, elevation or else]. The fact that you are using or borrowing a trig function is immaterial, it could be a piece of polynomial or any suitable model having same alpha argument.

MCADunk_2.gif

jmG

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