Questions about calculating with units in Mathematica.

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2
votes
1answer
40 views

QuantityVariable usage

When I try to run the following code, Mathematica gives me an error message: "Solve was unable to determine the units of quantities that appear in the input." ...
1
vote
1answer
38 views

Simplify CubeRoot of meter cubes

Why Mathematica doesn't simplify CubeRoot of meter cubes to meters? r = Quantity[10, "Meters"]; v = 4/3 r^3 Pi; CubeRoot[% * 3/4 / Pi] returns ...
1
vote
1answer
37 views

UnitConvert of a Quantity whose value is a function of a Quantity

I am having trouble with UnitConvert when the QuantityMagnitude contains an embedded ...
0
votes
1answer
37 views

Working with symbolic values in Quantities [duplicate]

I have the following expression: x Quantity[y, ("Milliwatts"*"Seconds"^2)/"Joules"] If I try to convert this to the SI unit, I would expect to get ...
0
votes
1answer
23 views

UnitConvert bar <-> Pa

I wanted to use the following unit cMax = Quantity[6.8221*^-9, "L/s/bar"]; But when calculating with it, I recognised there is some strange behaviour. So I tried ...
4
votes
1answer
73 views

Dimensionless quantities

I must admit that I don't think this problem is really new. However, I haven't found a post dealing exactly with this aspect of the issue. I am doing calculation using Quantities, but I have problems ...
1
vote
1answer
69 views

Unit System documentation

Is there any documentation on what consists of the unit system "SIBase","Imperial", "SI" and ...
11
votes
1answer
204 views

Possible bug: Quantity[2,“meters”] returns 2 None meters

I'm using 10.0 for Linux. Trial 1: Quantity[2,"meters"] 2 None meters Trial 2: Quantity[2,"Meters"] 2 meters Trial 3: ...
3
votes
2answers
132 views

Is there a build-in function converting a quantity to one with mixed units (such as feet and inches)?

For example, I want to convert 179 centimeters into 5 feet and 10.4724 inches instead of 70.4724 inches (as this website did). Maybe in the future I would need to convert days to {years, months, days} ...
8
votes
0answers
101 views

Why is this evaluation halved when adding units?

Why does this strange behavior occur when dealing with units and quantities? ...
1
vote
0answers
73 views

Geodesy without units?

Suppose I'm interested in the latitude of Los Angeles and I do the following: ...
0
votes
1answer
81 views

Unit conversion is not simplifying units

I'm running into what looks like an error. ...
0
votes
1answer
65 views

NIntegrate with units: unable to determine the units of quanitites that appear in the input

I want to integrate Planck's law of radiation in a certain wavelength intervall with units. I define some constants: ...
0
votes
0answers
59 views

Plotting Earth's position with units

I'm trying to plot the Earth position with the Sun in the origin. I have two lists like this: ...
2
votes
1answer
76 views

How do you get a country's GDP per capita in Euros?

Right now, I'm getting the data in U.S. Dollars and converting it to Euros like this: ...
4
votes
0answers
117 views

LowpassFilter in v10: unit issues?

Bug introduced in 10.0.0 and persisting through 10.0.2 or later I tried this with a clean start and no documents loaded. Now, evaluating the following on the documentation page for ...
0
votes
0answers
26 views

Why numerical functions can't digest InterpolatingFunction with units?

Answering this question gave me the idea that I must be missing something.. In brief, numerical functions generally 'understand' units: ...
2
votes
1answer
58 views

UnitConvert to Electronvolts converts to Electronvolts/Moles

The question probably is clear from the title. When I want to convert a kinetic energy, that contains the Molar Gas-Constant into Electronvolts I get eV/mol. ...
6
votes
3answers
134 views

Why does adding 6.1 seconds display as having added 6.099?

Why does adding 6.1000000 seconds to a DateObject display as having added 6.099? If I copy the Out[20] element from this picture, it contains the correct value: ...
3
votes
2answers
115 views

Something wrong with the way units are handled in V10

(This applies only to version 10) I obtain these two properties of silicon: a = ElementData[14, "CrustAbundance"] b = ElementData[14, "MeteoriteAbundance"] both ...
2
votes
2answers
134 views

Calculations with physical units [closed]

I really don’t get the Units in Mathematica 9. to work. I have tried this in the past for several times and at the end always run into some troubles. For example ...
2
votes
1answer
104 views

Using Manipulate[ ] with physical units

I'm a new user, and am trying to build a simple Boyle's law system in Mathematica. I want to include the units of the values, as I may need to perform some conversions later. If my quantities are a ...
7
votes
2answers
188 views

Convert units to String

Is there a way to convert compound units to string? For example, I have "Newtons"/"Meters"^2, how to I convert it to "N/m^2"? I know If I do the following ...
3
votes
1answer
73 views

Is there a way to display units in short label?

For example, forQuantityUnit[Quantity[1, "Meters"]], is there a way to display the results as"m" instead of "Meters"?
2
votes
2answers
177 views

How to specify units for ImageSize Option? [duplicate]

I'm trying out making a CDF and I want it to print within the margins of Letter paper. There is an ImageSize option that I would like to set; some plots will be in ...
2
votes
1answer
99 views

Converting in various currencies

I was just playing around with Mathematica converting some currencies: ...
15
votes
2answers
546 views

Where to see all Mathematica units [duplicate]

Is there a tutorial page that have all Mathematica units? I sometimes have hard time figuring out the correct unit spelling when using quantities
8
votes
2answers
890 views

Numerical value of physical constants Mathematica 10

Is there a way to use the physical constants in calculations and have Mathematica 10 figure out the final unit and numerical magnitude? When I try ...
1
vote
1answer
135 views

Solving equations with QuantityVariable

I'm trying to understand how to easily solve equations that use QuantityVariable. Why does this fail? ...
3
votes
1answer
132 views

How to dequantify units in mathematica?

Is there a function which applied to a quantity returns its numerical value so I for instance can fill it into my Predictorfunction?
3
votes
1answer
235 views

Wavelength, wavenumber, energy and frequency in a ruler

I would like to generate set of four axis relating wavelength, wavenumber, energy and frequency in an arbitrary range. Like in this image but without the labels such as "RADAR". The selection of ...
2
votes
0answers
74 views

Quantities formatting problem

So I've developed this simple code ...
6
votes
3answers
244 views
0
votes
0answers
96 views

Meaning of backtick in conjunction with units [duplicate]

In this fragment from an equation solution the backtick is used twice: ...
0
votes
0answers
52 views

Fitting data involving units

I want to fit some data to a model. However, if the data involves units in the independent variable, fitting seems not to work. As an example, consider the code ...
2
votes
4answers
141 views

Cancelling units in two-argument ArcTan

Consider ArcTan[3, -3] (* out: *) -Pi/4 ArcTan[3 a Sin[t/2], -3 a Sin[t/2]] (* out: *) ArcTan[3 a Sin[t/2], -3 a Sin[t/2]] However, we can fix the ...
0
votes
0answers
92 views

FindRoot with units error: Message text not found

This is sort of embarrassing. I'm working on a document to extol the virtues of Mathematica, and I can't get it to solve a relatively simple system of equations involving units. In this code, when I ...
0
votes
1answer
98 views

AstronomicalData not including units?

I like using mathematica to do my physics homework, and AstronomicalData is useful for that, but it doesn't seem to work properly with units. [the question is, at ...
2
votes
1answer
202 views

UnitSimplify returns unexpected non-SI unit combination

I am trying to get units working in mathematica in the following expression for diffusion: $D = {K_B T}/{3 \pi \eta L}$ My code is as follows: ...
-1
votes
2answers
125 views

Why won't Mathematica work with quantities or Quantity[]? [closed]

As you can see in the screenshot below, Mathematica is simply not evaluating any quantities. It is simply listing them as I wrote them. Could anybody give me a pointer as to why this may be?
7
votes
4answers
537 views

Suppress connection to Wolfram|Alpha when making unit conversions

I want to speed up calculations with unit conversions. I suspect primarily that some units evaluate from Wolfram|Alpha. Any way to prevent this automatically, so that Mathematica throws ...
-1
votes
1answer
97 views

Make Quantity behave reasonable with Degrees Celsius

When using a Quantity with the unit of "DegreesCelsius" multiplication doesn't work as expected. If you have 10 degrees and ...
3
votes
1answer
112 views

Choosing the units for plotting

I´m new to using units in Mathematica. I have read other similar posts about this issue but I haven´t found an answer so far. My problem is simple: I want to plot a certain function with a certain ...
1
vote
1answer
375 views

Unit of the frequency axis in BodePlot

I have a simple question: What is the unit of the frequency axis in the BodePlot? I searched the documentation, but only found this: The scaling functions can be specified as ...
1
vote
1answer
93 views

Grouping units more sanely

Would it be possible to get Mathematica to group units more sanely. For example the calculation: ...
4
votes
2answers
387 views

Using units and piecewise functions in Integrate

For simple cases, Quantities appear to be handled well by Integrate: ...
5
votes
0answers
182 views

Units: Custom-defined units possible?

Converting between revolutions per minute (RPM) and revolutions per second (RPS) is not straightforward for me in Mathematica. I know that $1\; \text{RPM} = \frac{2\; \times\; \Pi\; ...
3
votes
1answer
488 views

How to get the quantity of Physical constants?

I need to get the quantity of gravitational constant: QuantityMagnitude[GravitationalConstant] why this is not work? Already load the ...
1
vote
1answer
114 views

Caching data in Mathematica package

Consider the following: m=Quantity[1,"meter"] If I run the package, it will return 1m But when I load the package, the ...
3
votes
1answer
234 views

Why cant Mathematica 9 interpret this unit?

I'm using Mathematica 9.0.1. Sorry for using an image, but pasting code messed up the output formatting. I'd like to represent 25 Btu/(hr ft F). All units are spelled correctly as identified in ...