Units

[jdesai-2]

Hello,

Could someone please tell me what is wrong with these units. I hit the * and then inserted temp units (F)DUH ???

[LucMeekes]

That's Prime... Note that many of the temperature units are functions rather than 'simple' units, due to the fact that conversion requires more than simple multiplication with a constant.

Success!
Luc

[jdesai-2]

so what do I do? How do I insert units in alpha (co-eff of thermal expansion in/in*degF)

[DJF]

You need the delta temp, which is available in the temperature units.

[MJG]

What you want is change in °F (Δ°F), not °F.

[LucMeekes]

OK.

But then why does it produce an error message: "This value must be a scalar or a matrix".

???????

Luc

[MJG]

Short answer:

Because of poor error handling.

Slightly longer answer:

Because (as you noted) °F is a function.  You can't multiply by °F for the same reason you can't multiply by any other function (numerically).  You can only multiply by a scalar or matrix.  The °F function can only be applied to a scalar or matrix, not multiplied by one.

[ValeryOchkov]

Better use here R and K not F and C

[MJG]

Δ°F = R   and   Δ°C = K

The difference is merely display.

[ValeryOchkov]

I asked my colleague from NIST why you have R in the unit of entropy, and in thermal conduction unit F. He answered that it is easier to change the US Constitution than to teach American engineers to use R in the thermal conductivity unit, rather than F.