For questions related to conversion of units.

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0answers
19 views

nondimensionalise an equation

The per capita birth rate of a population is given by $r[1-a(N-b)^2]$, r,a,b are positive parameters,, write down a population model equation such of the form $dN/dt=f(N)$ Nondimensionalise the ...
0
votes
1answer
23 views

How to use the metric conversion

I know how to use the metric conversion (K h d b d m c) when converting length to length for example 1 m squared to cm, etc. But I want to know how to use the metric conversion when converting from ...
2
votes
1answer
50 views

Unit and dimension of angles

usually in physics (at least in the SI) angles are regarded as dimensionless. Is it possible to give a dimension (and a unit) also to angles and still have a system of units of measure as coherent as ...
2
votes
0answers
17 views

Units for Measuring Rotation of a 3-Sphere in Four Dimensions

In four dimensions, there can be two orthogonal axes of simultaneous rotation (of two planes), right? Does that mean that we can measure such rotations of a 3-sphere in solid angles, much as we ...
2
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0answers
11 views

Local Solid Angle Units

This is a cultural question: Are there any, even moderately or historically used, units that measure solid angles which are not steradians? Basically, is there a unit x such that x:sr::grad:rad?
0
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0answers
12 views

Nondimensionalisation of second order ODE

I need to make this equation non dimensional: $$F(t) = m \frac{d^2x(t)}{dt^2} + c \frac{dx(t)}{dt} + k x(t)$$ I tried with: m[kg] c[kg/s] k[kg/s^2] x[m] t[s] $x = x_{REF}* \overline{x}$ where ...
0
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1answer
21 views

SR Unit Conversion Speed

What is 72,000 km/hour in Système Relativistique (SR) units? I am getting 1/14490 or 1/14490th of the speed of light.
1
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1answer
36 views

Propagation of Uncertainties [closed]

I have five values for the volume of sodium hydroxide needed to neutralise a fixed quantity of hydrochloric acid, each trial with an uncertainty of 0.05 mL. If I take the average of these five values, ...
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3answers
37 views

Converting meter per second to km/h [closed]

Is there's a formula for converting Meter/s to Km/h? Example I need to convert 1200M/s to Km/h.
0
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0answers
13 views

Vectorization of multiplication of unit vectors

I have got unit vectors $n_{1}$ and $n_{2}$. Is there any way to define $\operatorname{Vect}(n_{1}n_{1}^{T}n_{2}n_{2}^{T})$ ?
0
votes
0answers
14 views

Convert a compound unit of heat to US units.

So, I must do the following conversion from my engineering textbook: $0.155 \frac{m^2 * ^{\circ} C}{W}$ to $\frac{^{\circ}F * ft^2 * hr}{Btu}$ I can get as far as: $0.155 \frac{m^2 * ^{\circ} ...
0
votes
3answers
22 views

How to convert a derived unit which contains degrees Celsius?

For instance, I have the following problem: convert: $\frac{{m^2}^{\circ}C}{W}$ to $\frac{ ^{\circ} F * ft^{2} * hr}{Btu}$ Take $x \frac{{m^2}^{\circ}C}{W}$ for instance, how would I convert it to ...
2
votes
3answers
35 views

How would you interpret this unit conversion question?

The following question is copied word for word from my textbook, which is what causes me to be so confused about the contradiction that it implies. The question: For gases under certain conditions, ...
1
vote
2answers
64 views

unitary mehod apply [closed]

যদি প্রতি 10মিনিট 3 বার গোলাবষন করে 6টি কামান 60ঘন্টায কোন দূগ ভাঙতে পারে তবে 5 মিনিটে 2বার গোলা বষণ করে যে সংখ্যাক কামান ঐ দূগকে ভাঙ্গতে Translation:- If 6 cannons by firing 3 times every 10 ...
1
vote
0answers
35 views

What formula can I use to calculate how much protein per 100 calories a given food has?

I have an Excel spreadsheet of 529 items all with calories, carbs, fats, and protein listed. I'd like to add a grams of protein per 100 calories column but my math ability is embarrassingly ...
0
votes
1answer
46 views

How many square millimetres are in 0.000075 square metres?

Doing my head in a bit.. $0.000 075 \times 100$ = in square cm, and times that by $10 =$ square mm but apparently I'm off by a couple of orders of magnitude.
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1answer
35 views

Setting Unknowns to 1

Suppose a square formation of troops 50 meters deep is marching with a dog in the middle of its back rank. The dog runs to the front of the formation, turns around instantaneously and runs back to ...
1
vote
1answer
19 views

Getting the number of significant digits in a multiplication/division.

What is the result of $$\frac{0.002843\cdot 12.80184}{0.00032}$$ with the correct number of significant digits? In the multiplication above, both have $7$ significant digits I think. Therefore ...
0
votes
1answer
15 views

Get the mass of air given the dimensions of a room.

The density of air is $1.19g/L$. What is the air's mass, in kilograms, in a room that measures $14.5\cdot16.5\cdot8.0$ feet? The room is is $14.5 \cdot 16.5 \cdot 8.0 = 1914$ cubic feet. We ...
0
votes
0answers
16 views

Trouble with rate calculation

Imagine spending $60$ seconds pressing a lever for food reward. Every time you press the lever, food comes out. Let's say that you emit $14$ responses in those $60$ seconds, and that the average ...
1
vote
1answer
66 views

Physics/Math conversion

I'm having difficulties solving this conversion. I know what to do at first but the way to set this up is a bit confusing:
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3answers
79 views

When should matrices have units of measurement?

As a mathematician I think of matrices as $\mathbb{F}^{m\times n}$, where $\mathbb{F}$ is a field and usually $\mathbb{F} = \mathbb{R}$ or $\mathbb{F} = \mathbb{C}$. Units are not necessary. However, ...
2
votes
1answer
41 views

Unit of value calculated by using integral

I have a really simple question that is driving me crazy! I have a program which can log power and the result is a log file which contains two arrays, one with time values that show when a power value ...
2
votes
1answer
27 views

According to Buckingham Theorem the rank of $A$ should be $2$

A physical system is described by a law of the form $f(E,P,A)=0$, where $E,P,A$ represent, respectively, energy, pressure and surface area. Find an equivalent physical law that relates suitable ...
2
votes
2answers
46 views

Conversion/compatibility of compounded physical units

This question is not so much asking about how to do something, but about whether it makes sense. For instance, converting miles per hour to kilometres per hour makes sense, because both terms have ...
1
vote
3answers
127 views

Units of Measure conversion

I was wondering if i could get some help trying to create a simple math formula. I recently was given an interview to work as a tier1 programmer and was asked to make a program. I made the whole thing ...
11
votes
5answers
3k views

How would multiplying money work?

This is a very silly question since nobody will actually do this because it makes very little sense in the real world but I just want to know how would it actually work if possible. For example let ...
0
votes
2answers
48 views

How to find average walking time per day

I have calculated that the total walking time for a person is 2990702 minutes in 801 days. I want to know his average walking time per day in minutes. I dont know if I need to convert minutes into ...
1
vote
0answers
75 views

Unit rules and style convention for division

I'm trying to figure out the preferred way to write unit expressions and division is causing me some confusion. I'm aware of the negative exponent notation, but here I'm looking for a solution using ...
0
votes
0answers
309 views

How to lay out the conversion of £ $(13 + v^{2}/52)$ per hour to £ per mile

"29. The total running cost of a ship per hour is £ (13 + $v^{2}$/52) where $v$ knots is the speed. if £ $C$ is the cost per nautical mile, write down an equation expressing $C$ in terms of $v$..." ...
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2answers
389 views

Why is 1 cubic meter 1000 liters?

Can anyone explain why $1\ \mathrm{m}^3$ is $1000$ liters? I just don't get it. 1 cubic meter is $1\times 1\times1$ meter. A cube. It has units $\mathrm{m}^3$. A liter is liquid amount measurement. ...
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1answer
30 views

Unit conversion equation

My company compares office rental price in multiple currency and units. Users can choose to view the price in USD per square foot or EUR per square metre or GBP per square yard, etc. For the sake of ...
0
votes
2answers
2k views

How to Convert Kilometers/Kilogram (km/kg) to Miles/Gallon (MPG)

I need to convert Kilometers per Kilogram to Miles per Gallon in order to calculate the Carbon Footprint of daily work commuters with vehicles using CNG (Nat Gas). In order to do this, I need to be ...
1
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2answers
408 views

In terms of units: is integration equal to multiplication and differentiation equal to division as a general rule?

The question From practical experience, I know that the unit of an integral - resulting from integration of an expression with respect to a variable with a unit (i.e. non-dimensionless variable) - is ...
0
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2answers
42 views

simple weight conversion

I need some help of mathematicians :D , So here is the problem So i am calculating calories in foods. If I google for "calories in banana" , I get this ...
2
votes
1answer
53 views

Is a unit conversion factor ever legitimately zero?

I was writing a unit converter for an industrial setting. To ensure that $\frac 0 0$ and $\infty$ never show up in the user interface I made a rule that no unit conversion factor can ever be zero. ...
0
votes
1answer
34 views

english to metric conversion with cubes

How do you convert $ft^3$ to $cm^3$? I can find an exact relationship online, but what if I just knew how many $m$ are in a $lb$ or something like that?
2
votes
2answers
100 views

How do you take the inner product of a vector whose components have different units?

How do you take the inner product of a vector whose components have different units? For example, what is the inner product of $\langle1m, 1s\rangle$ and $\langle2m, 3s\rangle$?
0
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1answer
25 views

Distance/measurement question! Help!

There is a question in a book that I am trying to solve. "A man usually rides his bike 1 kilometers per hour, yet the wind slows him to 6.76 kilometers for 26 minutes and 5.55 kilometers for 10. How ...
0
votes
1answer
62 views

How do you figure out the formula to convert between units?

I know that to, for example, convert from Fahrenheit to Celsius you subtract 32 and then divide by 1.8. I'm interested in how this type of formula can be developed. So, given two different sets of ...
0
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1answer
37 views

What is the measurement of side KL in a scalene triangle

Given: $\triangle FGH\cong \triangle JKL$ What is the measure of side 2 on triangle 2? Here is what I have. Triangle 1: Side 1: Unknown Side 2: Unknown Side 3: 12 Triangle 2: Side 1: Unknown ...
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votes
1answer
475 views

How strong can an earthquake be in measurement by the Richter scale in comparison to a weaker earthquake?

I've seen that the Richter scale measures the strength of any earthquake from 1 to 10 and I've also learned that a 2 is 32 (not 2) times as strong as a 1. What other comparisons of these numbers can ...
1
vote
1answer
3k views

Square Inches vs Inches Squared

I was just asked the question, is there a difference between 12 square inches and 12 inches squared. At first I assumed that 12 inches squared mean a square with sides of 12 inches. In this case the ...
1
vote
1answer
76 views

convert unit of measure mpg->lp100km

So, I have the problem to convert mpg to lp100km. I have tried to calculate them by hand, given that 1 mile = 1.60934 km and 1 gallon = 3.78541 litres, and it yields me like: 1 mpg = 235.133 lp100km ...
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votes
1answer
70 views

Double unit conversion metric to…US? [closed]

I had 5.52g/cm^3. I knew how to get it to 5.522x10^3 Kg/m^3. But now I not sure how to get it to lb/ft^3 correctly.
0
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2answers
102 views

Conversion of dosage based on body weight

Infant ibuprofen containes 100mg/5.0mL suspension. The recommended dose is 10mg/kg body to weight. How many mL of this suspension should be given to an infant weighing 18 lb? That's not a serious ...
5
votes
5answers
925 views

Is there a basic “unit” of measurement in math

I am wondering if there is a basic unit in math. $$3\ cm \times 2\ cm = 6\ cm^2$$ The $cm$ is a unit of measurement, but what about: $$3\ cm \times 2 = 6\ cm$$ Should the $2$ have a unit of ...
1
vote
1answer
34 views

How to normalise equations of the form $dy/dx=B$ and $d^2y/dx^2=A$?

So I am trying to normalise equations of the form, $$dy/dx=B \mbox{ and } d^{2}y/dx^{2}=A$$ If I define $y^{*}$ as; $$y^{*}=By \Rightarrow dy^{*}/dy=B $$ Is it also then true that, $$d(dy^{*})/dy = B ...
0
votes
1answer
38 views

Find total yards with LXWXH?

I have a box I need to cover all 6 sides with a single layer fiberglass fabric. The fabric comes in 50" or 28" widths. The dimensions of the box are 34" long; 15" wide; 12" High. How do I determine ...
0
votes
1answer
62 views

sub-nanoseconds resolution

I found following statement in a higher engineering mathematics reference book, But couldn't understand how it has been determined ? I have two values as follows: nanoseconds - could be any 30 ...