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\centerline{MONT 104N -- Modeling the Environment}
\centerline{Midterm Exam -- November 1, 2019}
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\noindent
{\bf Your Name:} $\underline{\qquad\qquad\qquad\qquad\qquad\qquad\qquad\qquad}$
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I.  In discussing amounts of water needed for irrigation of farmland,
a common unit of volume is the acre-foot.  One acre-foot of water is
the amount of water necessary to cover a flat field one acre in area to a depth of 
one foot.  Using the information below, answer questions A and B.
$$\matrix{ &1\ {\rm yard} = 3\ {\rm feet}\cr
           &1\ {\rm acre} = 43560\ {\rm square\ feet}\cr
           &1\ {\rm meter} \doteq 3.28\ {\rm feet}\cr}$$ 
\item{A.} (10)  How many cubic yards (${\rm yd}^3$) of water are in one acre-foot?
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\item{B.} (10)  How many cubic meters (${\rm m}^3$) of water are in one acre-foot?
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II.  The following table gives amounts (in tons) of materials of different types
recycled in Washington State in two years, 1986 and 1998.
$$\matrix{ {\bf Category} & {\bf 1986} & {\bf 1998}\cr
           {\rm Paper} & 391994 & 821994\cr
           {\rm Metal} & 9528 & 318710\cr
           {\rm Plastic} & 349 & 9871\cr
           {\rm Glass} & 48013 & 113338\cr
           {\rm Organics + Others} & 352 & 903466\cr}$$  
\item{A.}  (20)   Construct a chart {\it for 1998} showing the percentages
of that year's total accounted for by each of these types of materials.  Any reasonable 
type of chart is OK.
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\item{B.}  (10)  What percent of the total {\it for 1986} was accounted for by 
Paper and Plastic together?   
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III.   
\item{A.}  (10) In 2012, there were about $5.3 \times 10^4$ {\it alternative
fuel vehicles} (powered by electricity, ethanol, natural gas, etc.) sold
in the U.S.  By 2016, that number had risen to $1.6 \times 10^5$.
Construct a linear model for $AFV = $ number of alternate fuel vehicles, 
as a function of $t = $ years since 2012.  
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\item{B.}  (5) What does your model predict
about the number of AFV sold in 2017?  The actual number was $1.95 \times 10^5$
vehicles.  What is the percentage difference between the predicted number
(the ``comparison'') and the actual number (the ``reference'')?
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IV.  Wind power has emerged as one of the faster-growing methods
of electricity generation in recent years.  In 2016, the generating power 
of wind turbines installed around the world was about
$301$ gigawatts and it was increasing at about $33.2\%$ per
year.
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\item{A.} (10) Using this information, construct an exponential model for $WP = $
wind power generation as a function of
$t = $ years after 2016.  
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\item{B.}  (5) According to your model, how long will it take for the generating
power of wind turbines to reach $3000$ gigawatts?
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{\it Essay} (30)
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There is an ongoing movement at this point in history (i.e. 2019) 
that is especially strong in Sweden, where it known as {\it flygskam}.  
What does this Swedish word mean in English?  What actions 
are proponents of {\it flygskam} urging other people not to continue
doing, and what are their reasons for doing this?  Part of the underlying reason
for the existence of this movement is concern about how the actions are 
influencing greenhouse gas levels in the atmosphere.   What proportion of
current $CO_2$ emissions can be attributed to these actions and which people
are contributing most to this? 
While the recommendations of proponents of {\it flygskam} might make
a lot of sense from the environmental point of view, there are also 
certainly aspects of modern life that would be drastically changed if those
recommendations were adopted by everyone.  What would we be losing by following 
those recommendations?  Are the environmental benefits great enough to justify the 
costs to individuals and society of adopting those recommendations?  
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