Horsepower calculation & plotting

[ptc-5174372]

I'm trying to make a Mathcad document that calculates the performance requirements for a vehicle. Right now I'm trying to calculate the power requirements at various speeds and plot it on a graph. However, I bumped into a problem where it's telling me, "There are too many range variables." It's highlighting the variable for frontal area, which I have defined as A:=3.91m^2. Can anyone figure out why it's telling me that A is a range variable? I have attached the mathcad file for reference.

Also, I can't imagine I'm the first person to do this calculation in Mathcad. Does anyone have a document that already does this type of calculation?

Additionally, if you see anywhere where I could tighten up the syntax, please let me know. This is my first attempt with Mathcad.

Thanks!

Josh

[Werner_E · Accepted solution]

This is an often heard problem with Prime - Labels.

The cause for the error (the error message is misleading, to say the least) is that your variable "v" at the abscissa and the parameter "v" in your function P.aero at the ordinate have different Labels.

Solution is to either change the label of "v" at the abscissa from "none" to "Variable" (as in the attched) or change the label of the parameter "v" at the ordinate from "Variable" to "none".

[ptc-5174372]

That worked. It was indeed misleading.

Thank you!