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Re: DesignerUnits: Gallons divided by km yields an area.
*To*: mathgroup at smc.vnet.net
*Subject*: [mg115780] Re: DesignerUnits: Gallons divided by km yields an area.
*From*: David Carraher <david_carraher at terc.edu>
*Date*: Thu, 20 Jan 2011 06:32:23 -0500 (EST)
Hi,
I'm impressed with the conception and functionality of DesignerUnits.
Here's a simple example.
[Please excuse the formatting. In Mathematica the formatting is much more
readable.]
Question 1: On average, how much (what volume of) gasoline does my car use
to travel one meter if expends 4 gallons over 100 miles ?
There are more direct ways to solve this, but it's fun to divide gallons
by km to get an area.
a. Four gallons divided by 100 miles gives an area.
In[1]:= (4¡Egallon)/(100¡Emile)
Out[2]= 9.40858*10^-8¡Esq£»m£»
Imagine this as the cross section of a pipe that runs alongside the car.
The car consumes the gasoline corresponding to that contained in
the pipe section it travels along.
Now multiply that cross-section by one meter to get a volume.
That is how much gasoline is used along a one m stretch of road (assuming
constant consumption).
In[3]:= ((4gallon)/(100mile) *1¡Em)
Out[5]= 9.40858*10^-8¡Ecu£»m£»
Now convert back to gallons
In[6]:= ((4¡Egallon)/(100¡Emile) 1¡Em)/gallongallon
Out[6]= 0.0000248548£»gallon
In[7]:= Rationalize[%]Out[7]= 5/201168¡Egallon
Sure, you could have simply figured out how many meters are in a mile, but
it wouldn't have been as much funn.
Here are some questions that can effortlessly be addressed:
"How many miles per hour does my hair grow?"
"How many Hiroshima atomic bombs would it take to raise the temperature of
the Caribbean by 1 degree Celsius?
"How far does light travel in one nanosecond?"
It is particularly nice is to see the units displayed along the way, when
computations are chained.
David
To: mathgroup at smc.vnet.net
Subject: [mg115780] [mg115585] Re: DesignerUnits 2011-01-08 for Mathematica 8, 7, 6
From: "Vincent N. Virgilio" <virgilio at ieee.org>
Date: Sat, 15 Jan 2011 04:46:47 -0500 (EST)
The package includes a notebook for that. It produced a list of all
generated units by category. Forgot the name, but I, with diluted power of
concentration, found it somewhere in the install instructions.
Vince
On Fri, Jan 14, 2011 at 1:16 PM, DrMajorBob <btreat1 at austin.rr.com>
wrote:
> The web pages are comprehensive if, for instance, you don't need a list
of
> available units... unless it's there, but well hidden?
>
> Bobby
>
> On Fri, 14 Jan 2011 05:19:56 -0600, Vince Virgilio <blueschi at
gmail.com>
> wrote:
>
> Well Bobby, it "worked for me", and perhaps completed sooner than
>> expected! (I went to sleep after launching it.)
>>
>> A quick glance at this package's web pages showed them to be
>> sophisticated, comprehensive, and convenient---a good mix. The
>> "backgrounder" page has a directness that is almost poetic.
>>
>> Haven't used it yet, so we'll see how it plays out.
>>
>> Vince
>>
>>
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