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Part 1: Driving to the Limit
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;; 1. In 2006 there were about 244 million vehicles on U.S. roads, while the
;; country.FN"s population was 299 million. How many people were there for each
;; car in the United States in 2006? (round to the nearest hundredth) _________
;; people.
(setq people-per-cars (/ 299 244))
;; 2. a. How much time would it take someone to get to work if he/she were
;; traveling 20 miles at 30 miles per hour?
;; (Use the formula: Time = Distance/Rate) ______ hours. How many minutes is
;; this? ______ minutes.
(setq hours (/ 20 30))
(setq minutes (* hours 60))
;; 2. b. As the number of cars on the road increases, the average speed a car
;; can travel decreases. How much time would it take that same person to get to
;; work if he/she could only travel at only 15 miles per hour? ______ minutes.
(setq new-minutes (* (/ 20 15) 60))
;; 2. c. What is the difference in time between the two speeds? ______
;; minutes.
(- new-minutes minutes)
;; Double!
;; 3. In 1980 there were 155,796,000 vehicles registered in the U.S. and our
;; nation.FN"s population was 227,726,000 people.5 In 2006 there were 244,166,000
;; vehicles and 298,755,000 people.
(defun percent-change(new old)
(* 100 (/ (- new old) old))
)
;; 3. a. What was the percent change in number of registered vehicles from 1980
;; to 2006? ______.
;; (% of change = amount of change/original amount)
(percent-change 244166000 155796000 )
;; 3. b. What was the percent change in U.S. population during the same time
;; period? _______.
(percent-change 298755000 227726000)
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Part 2: Gassing up
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;; 4. In the United States the average car burns 560 gallons of gasoline each
;; year.7 There are about 244 million autos in the U.S.8
;; a. If a person drives 10 miles each way to work and averages 22 miles per
;; gallon, how much gas is used each day?_______ gallons.
(* 10 2 (/ 1 22.))
;; b. If a person drives 10 miles each way to work in a gasoline/electric
;; hybrid that averages 50 miles per gallon, how much gas is consumed each day?
;; _____ gallons.
(* 10 2 (/ 1 50.))
;; c. If 30 people take a bus 10 miles to work and back and the bus averages
;; 6.5 miles per gallon, how much gas does the bus consume each day?______
;; gallons. What is each passenger.FN"s share of gas consumed?______ gallons.
(setq bus-gas-use (* 10 2 (/ 1 6.5)))
(setq average-use (/ bus-gas-use 30))
;; d. Which of the options above is the most energy efficient people-mover?
;; __________________.
;; The bus!
;; 5. How many gallons of gasoline do all of the cars in the United States,
;; combined, burn each year? ______________ gallons.
(* 244 1e6 560)
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Part 3: Human Masses, Greenhouse Gasses
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;; The "greenhouse effect" is caused by a layer of gases in the
;; atmosphere. These gases trap the sun.FN"s warmth just like a greenhouse. If we
;; add too many "greenhouse gases" to the air, the planet may get warmer
;; and warmer. Carbon dioxide (CO2), one of these gases, is released into the
;; air when gasoline is burned. Nationwide, transportation accounts for 30% of
;; all CO2 emissions.9
;; 6. To describe how much of something is in the air, scientists use the
;; expression .FN4parts per million,N! or N4ppm.N! (For example, if you had a million
;; dots, one of which was orange, while the rest were purple, the concentration
;; of orange dots would be one part per million.) In the year 1900, the
;; concentration of CO2 in the air was around 270 ppm. In 2006 it was 382
;; ppm.10 What percent increase is this?_________.
(percent-change 382 270)
;; 7. Scientists estimate we need to reduce CO2 emissions to 7 billion tons per
;; year by 2050, in order to stabilize global temperatures.11
;; a. By 2050, the population of the world is expected to grow to 9
;; billion.12How many tons of CO2 would each person be allowed to add to the
;; atmosphere if permits were allotted equally to all people? ______________
;; tons.
(setq each-person-ton (/ 7 9))
;; b. How many pounds per day could each of us produce? (1 ton = 2,000 pounds)
;; ________ pounds.
(setq daily-quota-pounds (* 2000 (/ each-person-ton 365)))
;; c. Driving one mile releases approximately one pound of CO2 into the air, on
;; the average.13How far could you get on your allotted CO2 emissions by car?
;; _______________ miles.
daily-quota-pounds
;; d. What are some things you could do now and in the future to limit your
;; share of CO2 production?
;; 8. a. If Americans drive a total of 3 trillion (3,014,000,000,000) miles
;; each year, how many tons of CO2 do cars release each year? 14
;; _____________________________ tons.
(* 3.014 1e12 (/ 2000))
;; b. If the average fuel efficiency increases from about 22 mpg to about 44
;; mpg, but the number of miles driven by all the cars on the
;; roads doubles from 3 trillion to 6 trillion, how much will we have changed
;; our total CO2 production? ____________.
;; Nothing at all....
;;
;; -------------------------------------------------------------------
;;
;; Notes and Sources:
;; 1, 2, 4, 5, 6, 8, 14
;; U.S. Census Bureau, Statistical Abstract of the United States: 2009.
;; 3, 9Recent Trends in U.S. Greenhouse
;; Gas Emissions, United States Environmental Protection Agency web site
;; www.epa.gov. 7
;; Energy Information Agency. 10National Oceanic and Atmospheric Agency
;; (NOAA). 11R. Socolow, S. Pacala, -Y.AN4A Plan to keep Carbon in Check,N!
;; Scientific American, 25, 2006. 12World Population Data Sheet 2009,
;; Population Reference Bureau, www.prb.org 13American Forests Association web
;; site, www.americanforests.org.