I posted the following on the Google+ group comp.soft-sys.math.mathematica and had no luck with responses. I've done a Google search and, to the best of my ability, used the documentation center.

The post I made was as follows:

I continue to receive "Unable to interpret unit specification m/s" (for example, but almost anything I attempt returns this message) with input: UnitConvert[55 mi/h,"m/s"] or UnitConvert[55 mi/h,m/s] or any other combination of quotes, omitted quotes, etc. Even the prediction/suggestion box, when I execute Quantity[55,"mi/hour"}, after it returns 55 mi/h, if I type in any combination of m/s, "m"/"s", "m/s", etc. into the box that opens when I select "Convert" in the prediction box yields the same "unable to interpret unit specification.

What am I missing? (As you may gather, I'm a Mathematica novice.)

  • 1
    $\begingroup$ Try UnitConvert[Quantity[55 , "Miles"/"Hours"], "Meters"/"Seconds"]. $\endgroup$ Dec 18 '12 at 21:09
  • $\begingroup$ That's the sam as the answer I posted to MathGroup this morning. (Which raises a protocol/meta-question: should folks be posting the same question to both MathGroup and here?) $\endgroup$
    – murray
    Dec 18 '12 at 21:24
  • $\begingroup$ @murray ask it on Mathematica Meta. I believe it was discussed, but I cannot remember where. $\endgroup$
    – rcollyer
    Dec 18 '12 at 21:47
  • $\begingroup$ @murray meta.mathematica.stackexchange.com/q/367/16 $\endgroup$
    – acl
    Dec 18 '12 at 22:24

It seems, if you are not going to use the "proper long name", you need to use Quantity Try

UnitConvert[Quantity[55, "mi/hour"], Quantity["m/s"]]
  • $\begingroup$ +1, exactly. You must use Quantity, otherwise it may not recognize what you are doing. $\endgroup$
    – rcollyer
    Dec 18 '12 at 21:20
  • $\begingroup$ Thanks.Those work but the UnitConvert page in the Documentation Center and the sure doesn't make it seem like all that is necessary. For example: UnitConvert[Quantity[8.2,"Miles"],"Pounds"]]. $\endgroup$
    – user5091
    Dec 18 '12 at 22:16
  • $\begingroup$ @user5091, There's a "full" name for each unit, and then there are ways that you can type it that get properly recognized because WolframAlpha understands what you mean. If you do InputForm[Quantity["m"]] you'll see what I mean. That translantion only seems to be done inside Quantity. If you use the "full" name, you don't need the Quantity in UnitConvert $\endgroup$
    – Rojo
    Dec 19 '12 at 0:48
  • $\begingroup$ I agree however that it shouldn't be necessary to type Quantity. Perhaps it will be changed in the next upgrade. $\endgroup$
    – Rojo
    Dec 19 '12 at 0:50

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.