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# Questions tagged [units]

Questions about using, converting, or interpreting units of measurement in Mathematica.

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61 views

### Unitless quantities

There are many cases in science where a quantity should end up unitless. Yet the units capabilities of Mathematica seem to have a problem with such situations. For example: ...
71 views

### How can I add units to variables inside Manipulate?

I've created a Manipulate expression with many variables. I would like each of these variables to have associated units as in the standard Quantity[Value,"Unit"] so that I can easily enter the values ...
803 views

### Why do I get QuantityUnitsPrivateToQuantity when trying to use units?

I'm unable to use units in mathematica (10.3.1) When I do Quantity[500, "Feet"] + Quantity[50, "Meters"] the answer I get is ...
37 views

### What is used for the % symbol in mathematica? [duplicate]

Im new in mathematica i want to know logic about this program. I got this code: {{vo, vn, Ii}} = {vo, vn, Ii} /. %; i know that the syntax /. is for replacement but i dont know whats going on with ...
1k views

### How to get Planck length in meters to 6 decimal places

I want Mathematica to format quantities to more decimal places than the default. For example I have tried ...
40 views

### Manipulating a ParametricFunction to handle units

I have a pretty nice way to handle units on a result from NDSolve, which basically consists of converting all of the units to SI, stripping them, calling NDSolve, and then putting the units back. I'll ...
34 views

### TargetUnits aren't working as expected on an InterpolatingFunction

Short version: My understanding of the use of TargetUnits in a Plot statement is that if the function being plotted has units, MMA will attempt to convert the output of that function to the unit form ...
102 views

### Very slow rendering of Quantity

I noticed since Mathematica v12 a very slow frontend when rendering the Units. Easy to show: Quantity[Range[1, 100], "Euros"] Takes (timed with a stopwatch) ...
27 views

### SemanticImport changes “string” type to “quantity” type--how to change during import or after import?

This question may overlap with other questions about the quirks of SemanticImport, but I don't see this specific wrinkle on StackExchange and I hope it will be a simple answer to help me and others ...
1k views

### Automatically add appropriate prefix to Quantity

Is there a function that automatically adds the appropriate prefix to a Quantity object? For example, I would like a function ...
27 views

### Problem with UnitConvert with a list

I'm studying this part of the course units convert I have two list the first: is in Megaparsec and I need to transform it to kilometers ...
670 views

### Physical (and other) constants

As Mathematica documentation likes to say, "As of Version 9.0, physical constant functionality is built into the Wolfram Language". After clicking on the ">>", one ...
67 views

### NDSolve and Quantity[]

I'm working on a set of relatively basic ODEs of a physical pendulum and motor: \left\{\text{jb} \theta ''(t\text{s})+\text{rb} \theta '(t\text{s})+\alpha \sin (\theta (t\text{s}))+\mu \tan ^{-1}\...
83 views

### Scientific Notation for Quantities

I am using Quantities (units) in Mathematica 11.3 and would like to express the numerical portion of the output in scientific notation. The command ...
52 views

### How to change all stock prices to USD?

I want to create DateListPlot that compares prices of cellphone manufacturers' stocks over the last 13 years. Stocks include Nokia, Blackberry, Samsung, LG, Motorola, and Sony-Ericsson. The problem is ...
131 views

### Specify set of base units to use in UnitConvert

I am trying to convert arbitrary units to CGS. I know this can get a bit tricky with ESU, but for this question that does not need to be addressed. What I would like to do is to give a quantity-to-...
666 views

### Mathematica seems confused about Kilograms vs KilogramsForce

This does what I expect: Quantity["Kilograms"*"Meters"] // InputForm Quantity[1, "Kilograms"*"Meters"] This, on the other hand, bungles the units: ...
50 views

### Why does the TimeObject seem to lose precision? (+ note on units)

According to the documentation (11.0.1.0) Shorter lists can be used in TimeObject[{h,m,s}], which represents the time to whatever accuracy is specified: {h} is not [sic?*] treated as being ...
185 views

### Why does using different units but same physical value give different result?

I'm trying to define a variable with the value of the thermal constant $V_T$. The value of the thermal constant is given in Volts as $V_T = \frac{k T}{q}$, where $k$ is the Boltzmann constant and $q$ ...
4k views

### Simpler input for the new unit support

I've been playing with the new unit support in Mathematica 9. It seems very useful, but the syntax is very verbose. Instead of typing: ...
66 views

### Bizarre Problem with Wolfram Knowledgebase: Extracting Values

[System: Mas OS Mojave; Version: 11.3.0.0] I tried to use the knowledgebase, because why not, but got a strange result: I also tried another lookup for good measure: Plaintext code: EntityValue[{...
145 views

### Get Isotope Data and Electron Mass in Same Units - kg and Kilograms

I'm trying to find the nuclear mass of $^{238}\text{U}$. To do this, I subtract the electron mass from the atomic mass. I'd like to find the final answer in kilograms. I'd also like to use Mathematica'...
64 views

### Custom conversion rules in UnitConvert

I want to make UnitConvert operate on custom units with special rules. For instance, I would like to be able to convert between ...
673 views

### Using physical dimensions in Mathematica DSolve

I would like to calculate a system of two differential equations in Mathematica using DSolve, like: ...
920 views

### How to convert between various ItemSize/ImageSize units?

How can one convert between the implicit units used by Grid (ems and line height for horizontal and vertical dimensions) and printers points (in ...
58 views

### Convert time interval to mixed units without leading zeros

Let's say I have time intervals in seconds. I am looking for a method that produces the following conversions: 3660 => ...
102 views

### Problem using UnitConvert

As we know in physics, power = torque * (angular velocity). But when I use UnitConvert to convert a quantity expressing power/(angular velocity) into newton-meters, ...
218 views

### Convert decibels to amplitude - Built-in function

Is there a built-in function to convert decibels to amplitude in Mathematica? I tried with: UnitConvert[Quantity[40, "decibels"], "amplitude"] but it does not ...
70 views

### Join on QuantityArray

I need to merge two QuantityArray objects of mixed type. My first attempt looks something like: ...
125 views

### Multiplying quantities by scalars in Mathematica 11.3

I'm no longer able to multiply scalars by quantities in Mathematica 11.3. In previous versions the code 3*Quantity[1, "mm"] evaluated to ...
72 views

### FinancialData returns undefined Units for Volume or randomly fails

Recently FinancialData["IBM","Volume"] started failing and when it does randomly work, it returns Quantity[3073167,Shares] but ...
45 views

### Interpreter for Quantities without magnitude

When using a quantity interpreter on a unit without magnitude, the interpreter fails, but works fine on quantities with magnitudes. Ex: ...
73 views

When I do ...
1k views

### Conversion between GB and MB (and KB)

UnitConvert[Quantity[1, "GB"], "MB"] Quantity[1000, "Megabytes"] Which is NOT something we would normally expect. Is this a bug? How can I use 1024MB =...
606 views

### Why is this evaluation halved when adding units?

Bug introduced in 9.0 or earlier and persisting through 11.2 or later Why does this strange behavior occur when dealing with units and quantities? ...
42 views

### Plot[func,…] shows incorrect function, but ListPlot@Table[func,…] is correct

When trying to Plot the function 1/(1 + E^(((e + Quantity[-7.05, "Electronvolts"]) *(Quantity[1, 1/("BoltzmannConstant")]))/T)) I get an incorrect plot ...
85 views

You can Round Quantitys. For example, how many inches are in a meter? ...
6k 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 ...
3k 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 ...
293 views

### Quantity and Trig functions

I have a bunch of data to which I've assigned units using Quantity, including some angular measurements in degrees. I'd like to be able to use these measurements ...
304 views

### How to prevent Quantity calculations from converting units

I have an accrual calculation that I would like to preserve the units even though they are of the same dimension (e.g. time). For example, I would like the following ...
494 views

### How do I properly use Quantities (units) in plots?

I'm having some problems making plots with quantities in Mathematica Online 11.3.0. If I make a plot that is defined with the $x$-axis as an independent quantity (e.g., 0 to 3 seconds) and the $y$-...
877 views

### Can I format units using engineering prefixes?

I'm in the early stages of learning about units. It seems easy enough to express numerics and symbolics in units, but what I would really like to do is append engineering prefixes (km, mA, MW, etc). ...
97 views

### Is it possible to get the name of a physical quantity related to a quantity, e.g. watts->power?

Is there a way to get the name of the physical quantity given by a particular unit? For example, QuantityUnit[Quantity[1, "Henries"]] returns ...
106 views

### How to Reduce an inequality with QuantityVariables?

Without QuantityVariables I can Reduce a Quantity inequality. ...
35 views

### Buggy IntervalUnion with Quantities?

IntervalUnion can give wrong output when used with Quantity: ...
101 views

### Plotting Time Series in the same currency value [closed]

I'm working with Financial Data and I'm using this code: ...
111 views

### Solving Equations with units is not working

I have the code Clear[distance, time, Vavg]; Solve[Quantity[Vavg, "Meters"/"Seconds"] == Quantity[distance, "Meters"]/Quantity[time, "Seconds"], distance] ...