Calculating with Units
- To: mathgroup at smc.vnet.net
- Subject: [mg93997] Calculating with Units
- From: Nikolaus Rath <Nikolaus at rath.org>
- Date: Mon, 1 Dec 2008 07:02:08 -0500 (EST)
Hello,
Until now, I have always defined my units manually in terms of
the 4 base units Kilogram, Meter, Coulomb and Second:
Newton = Kg Meter / Second^2;
Joule = Newton Meter;
Henry = Weber / Ampere;
Weber = Volt Second;
etc.
This allows me to evaluate expressions like
B = (\[Mu] Ii)/(2 \[Pi] r);
B /. { r -> 20 Meter, \[Mu] -> 4 \[Pi] * 10^-7 Henry/Meter,
Ii -> 2 Ampere}
% / Tesla
and directly see if the units in the final result are correct.
But since all these units (and many more) are already defined in the
Mathematica Units package, I was wondering if there isn't a way to use
that package in the same way. Unfortunately, it doesn't seem to
simplify the units, i.e. when I enter
(Ampere Henry)/(Meter Meter) // Simplify // SI
I get the same expression back. What I would like to get is either
"Tesla" or "Kilo Gram / (Coulomb Second)". Is there a way to
accomplish this?
Best,
-Nikolaus
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