For questions related to conversion of units.

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1answer
36 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.
1
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1answer
33 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
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1answer
17 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
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1answer
14 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 ...
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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
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1answer
42 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:
21
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9answers
7k views

Why do we require radians in calculus?

I think this is just something I've grown used to but can't remember any proof. When differentiating and integrating with trigonometric functions, we require angles to be taken in radians. Why does ...
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3answers
52 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
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1answer
31 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
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1answer
23 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 ...
5
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3answers
1k views

Arbitrarily discarding/cancelling Radians units when plugging angular speed into linear speed formula?

Why is the radians implicitly cancelled? Somehow, the feet just trumps the numerator unit. For all other cases, you need to introduce the unit conversion fraction, and cancel explicitly. Is it ...
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3answers
44 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 ...
2
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2answers
23 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 ...
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5answers
2k 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
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2answers
32 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
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0answers
27 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
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0answers
163 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
111 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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2answers
96 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 ...
1
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1answer
26 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
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2answers
453 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
vote
1answer
1k 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 ...
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2answers
36 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
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1answer
40 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. ...
2
votes
2answers
97 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 $\langle2m, 3s\rangle$?
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1answer
28 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?
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1answer
49 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
18 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 ...
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votes
5answers
728 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 ...
0
votes
1answer
32 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
277 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 ...
5
votes
4answers
16k views

Units of a log of a physical quantity

So I have never actually found a good answer or even a good resource which discusses this so I appeal to experts here at stack exchange because this problem came up again today. What happens to the ...
2
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1answer
224 views

Radian, an arbitrary unit too?

Why is the radian defined as the angle subtended at the centre of a circle when the arc length equals the radius? Why not the angle subtended when the arc length is twice as long as the radius , or ...
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1answer
58 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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1answer
38 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.
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2answers
74 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 ...
0
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2answers
181 views

Converting squared or cubed units

At the moment I am going from square meters to square yards. One meter is $1.0936$ yards. So I figure $1\text{m}^2 = 1.0936 \text{yards}^2$ I know it isn't but I want to learn a good systematic ...
0
votes
2answers
105 views

How many inches are in 7.94 feet?

Question: the height on my land is 7.94 feet noted by a surveyor on a Certificate of Elevation form. In layman's terms, that is 7 feet and how many inches? or how much of an inch is it short of 8 ...
0
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1answer
60 views

If the cost per minute is $\$0.032$, is the cost per hour $\$1.92$ or $1.92$¢?

I hope someone can help me with this problem. The cost per minute to make a phone call is $0.032, I'm that multiplying this by 60 will get total cost per hour. ...
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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 ...
3
votes
2answers
2k views

Difference between “sq km” and “km sq”

If I have a square with side $2\ \text{km}$, what is its area: $2\ \text{sq km}$ or $4\ \text{km}^2$?
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vote
2answers
364 views

Convert angles from the sexagecimal system to centesimal one

How do you convert angles from the sexagecimal system to centesimal one? For example 63 degrees 14 minutes 51 seconds reduced to centesimal ?? Here's how it's done but I don't understand the ...
0
votes
1answer
26 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 ...
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2answers
59 views

How can I Express It In DMS FORM? [closed]

This (below) 35.24 degree 160.11 degree -381.87 degree 280.99 degree -525.66 degree 85.372 degree
0
votes
1answer
53 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 ...
2
votes
1answer
34 views

Division of Compound Units

Why are compound units of speed,density etc. expressed in terms of a numerator and a denominator? For example, m/s, kg/m3 etc. I've always understood division as either the inverse of multiplication, ...
1
vote
1answer
60 views

Taylor's series and the function argument dimension

I've stumbled over an interesting question. In $\cos(x)$, $x$ is measured in, say, radians. When I expand cosine in Taylor's series, I have the terms with $x^3$, $x^5$ etc. so I am summing up ...
0
votes
1answer
12 views

How to determine a deficit of base 10 exponent from a minimum unit

I'm trying to determine if a number includes a portion in deficit of a base 10 exponent from a minimum unit. For example, given a minimum unit of $0.01$, $1$ would pass the test, but $1.001$ would ...
1
vote
1answer
170 views

What are the units of Singular Value Decomposition components?

I have a symmetric variance/covariance matrix $A$ which is of size (27 x 27). I know that it's rank deficient (rank = 21). I also know that the units of $A$ are $m^2$. I am trying to use Singular ...
0
votes
1answer
32 views

I have trouble understanding simple equality passage

I don't know why I always have trouble with these things, there is something that must do 'click' in my head. Knowing that 1000000 cm³ = 1 m³, how do you get that ...