# Questions tagged [unit-of-measure]

For questions related to conversion of units.

196 questions
0answers
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### Quesiton about finding bulk and particle density

The mass of the moist soil = 8126 g; the mass of the dry soil = 7239 g; the volume of the water needed to fill the hole = 3810 cm3. What is the total porosity (%) of their soil? The hole is about 10cm ...
1answer
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### weight of ideal soil (given 2 different densities)

QUESTION - What is the total weight, in pounds, of $1$ cubic meter of an ideal soil including the soil solution. You can assume that the particle density of the soil solids = $2.65$ Mg/cubic meter and ...
14answers
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### Is the percentage symbol a constant?

Isn't the percentage symbol actually just a constant with the value $0.01$? As in $$15\% = 15 \times \% = 15 \times 0.01 = 0.15.$$ Isn't every unit actually just a constant? But why do we treat ...
1answer
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### How to convert $\ kWh/m^2$ to $\ Joule/kg$

How to convert $$\ kWh/m^2$$ to $$\ Joule/kg$$ I want to compare the radiation produced by the sun over a location (where I live in, measured in $\ kWh/m^2$), to the radiation a person gets from a ...
0answers
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### Why do not we use radian unit sign well? [duplicate]

Mentioned the word) Radian-unit-sign, rad, unit, radian, pure number, ratio, symbol, speed, distance, time
2answers
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### Difference between Celsius and Fahrenheit leads to unexpected observations.

Say city A has a temperature of 54 F(12.2 C) and city B has a temperature of 44 F(6.7 C). Their difference is 10 F which is about -12.2 C. I mean what!? This means that 44 F(6.7 C) > 54 F(12.2 C) or ...
0answers
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### Are percentages scalable?

I have data made up of percentages but no idea how they were calculated. I am using this data to demonstrate Benford’s Law and so far it does follow this law! But one of the properties of sets that ...
3answers
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### What is a valid unit of measurement?

Ok, so this is a bit of an odd question. It is sort of a physics question, but I felt it was more appropriate here. Feel free to suggest another venue. Let's just look at a simple example. We'll use ...
1answer
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### Medical Units into grams

I'm trying to figure out how to divide a medicine up by millions of units into grams or half grams and figure a group like this who play with various math problems might be able to help: What I know ...
0answers
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### Mixing two different essential oils to their maximum safe dilutions in one carrier oil

I want to mix cinnamon bark essential oil (safe at a maximum 0.5% dilution) with tea tree essential oil (safe at a maximum 15% dilution) in shea butter. Shea butter is safe undiluted. The above ...
0answers
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### Conversion from drops to mgs

If the bottle has 500mgs in it and 20 drops equals to 6ml. How many drops do I need to order to get 350 mgs?
4answers
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### Why km$^2$ and not (km)$^2$?

Why don't km$^2$, cm$^3\ldots$ follow the precedence rule of power over product ? One should write (km)$^2$ since it is one million square meters.
0answers
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### Determine measure unit.

Determine a measuring unit of $B$ and $k$ if $T$ is a temperature in Kelvins, $t$ is time in seconds and $L$ is the length in meters. $$T(t)=T - (1 - e^{-kt})(1 - B - L^2)$$
1answer
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### Air pollution and measurements: deciliter vs cubic meters

If a deciliter of air has 5000 micrograms, how much would be in a cubic meter? (Particulate matter smaller than 2.5 microns is measured in decileters, larger than 2.5 are generally measured in cubic ...
3answers
196 views

### How much longer does it take to paint a similar box with $5$ times more volume?

This is a question from a precalculus class that I'm a TA for. You build a box that has a volume of 100 cubic feet. It takes two people ten minutes to spray paint this box. How many minutes does it ...
2answers
92 views

### Why is the area of a rectangle with sides a and b defined as axb?

Imagine $a \times b$ was not defined and we need to come up with something. Here is the justification I could come up with: Suppose, I have to measure this thing called area, I have to come with a ...
1answer
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### What are the units of the gravitational constant of the universe $G$?

This is a homework question from a precalculus class that I'm a TA for. The force $F$ between two bodies of mass $m_1$ kilograms and $m_2$ kilograms whose centers of mass are a distance $r$ ...
1answer
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### Explain units for negative exponent

From a textbook of recent publication; "The average radiation on the Earth’s surface is $340 W m^{−2}$." I get the 340W. I presume m is meters. How does a minus 2 affect a meter, rather a square ...
3answers
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### Is 0.1 km equals to 100.0 m (in context to significant figures)?

The number of significant digits in 0.1km is 1 and we know that 1 km = 1000m. This then implies that the 0.1 km is equal to 100.0 m, but the rule says the change in units doesn't affect the number of ...
2answers
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### How do significant figures work in a cross unit division?

In one of my problems, I needed to find a slope on a graph with different units in physics. 309 cm² - 0.0 cm² / 100 cm - 0.0 cm The answer is A = 3.09 r² with A being area and r² being radius ...
0answers
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### Quadratic relationship between units?

Most units I can think of in a given quantity is defined with a linear relationship between them. Is this true for all units? I'm thinking of generalizing conversion factors on this formula: y = x * ...
0answers
38 views

1answer
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### Where can I find info on algebra with units of measurement?

If you add two magnitudes with same units you get an answer which is in the same units, but adding different units "does not make sense". But this is not true with multiplication, because you can ...
0answers
80 views

### A paradox regarding a being able to measure a distance between two points with an infitely accurate distance unit

This question is related with the Cardinality of the continuum and Zeno's paradox about Achilles and the tortoise regarding the concept of infinity. I would like to know if the following guessings are ...