Energy and the Environment
Energy and the Environment PHYS 3070
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This 20 page Class Notes was uploaded by Mrs. Peter Toy on Friday October 30, 2015. The Class Notes belongs to PHYS 3070 at University of Colorado at Boulder taught by Stephen Wagner in Fall. Since its upload, it has received 6 views. For similar materials see /class/232102/phys-3070-university-of-colorado-at-boulder in Physics 2 at University of Colorado at Boulder.
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Date Created: 10/30/15
ea A es E Nu J Y J c oZ Ca2 EnErgy Thus nute tnattur eyery atum ufcarbun we pruuuee une muJeque ut 002 Tmswmtum uuttu pe une uttne majurfacturs mtne merease m earpun utuxtue m tne atmuspnere a greennuuse gas J Eaen reactmn wttn a earpun atum m tne euattur EXampJE nas an energy ut1o1E Joules Tms seems We a tmy number But t ts unJy une earpun atum Huvv many atums are tnere m 12 grams ut earpun7 Avagadru s Number 6 gtlt1E23 atums per muJE per 12 grams utearpun A1 puunutump ut uaJ nas apuut m5 atums ut earpun Tnus tne tutat energy trum tms enemteat reaettun ts Total Energy Energy per Carbon Atomx Carbon Atoms Total Energy 10 JoulesAtomgtlt10 Atoms 107 Joules Chcker Questmn VWH tms energy W James appruxtmatety new many teet ean we ratse a sum tp ear7 Assume munn Ef ment use ut Sututtun Energy 107Jgtlt Energy7x10 ezbs n atea dune ts hmng a SEIEIEI Jbs ear X 23mm feet 7 X m bes gg gg hmquot Wnere tstne energy gwen un tms tapew New Energy Umt Fund CaJune urgatune tFuuu CaJDHE MEAJoues Energy Unit Calorie and calorie calorie Energytu enange tne temperature um gram utwater y 1 C Calorie or Food Calorie or kilo caloriel Energytu enange tne temperature ut t Wurgram utwaterpy 1 C Tnus a Fund CaJune ts aetuaHytne same as man came wmen ts tne physms ur enemtstry term So really that is 1000 physics calories British Thermal Unll BTU Energy required to change the temperature of1 pound ofwater by 1 F er Question Table 26 says that the best coal Anthracite which is 88 carbon has an energy content of 13300 Btu lb 30 how many degrees can you raise the temperature of 260 pounds ofwater with the energy 39om one pound of coal A 5 derees Fahrenheit C 250 degrees Fahrenheit D 3000 degrees Fahrenheit E 40 degrees Celsius 1 Jelly donut 250 Calories 002 HzO Energy How many Joules of energy is this 13300 Btu raises thetemperature of1 lbs ofwater by 13300 F 13300 Btu raises thetemperature of 260 lbs ofwater by 13300260 50 F 1000 calories 418410ules 7106 Joules t 1Calorie t lcalorie 7 39 at ifwe compare this 1 million Joules 39om the donut to the Potential Energy ofa 60 kg object at a given height H What is that height H PE mgH PE 106J0ules m g 60kgx98msz 7E7 106J0ules mg 60kg x98msz H 1700 meters or 5000 feet Biological mechanism needed for Other forms of Energy Demonstration with hammering a nail into a board 1 Work is done by the person to give Kinetic Energy to the hammer 2 The hammer then does work on the nail to give it kinetic energy the nail moves with some veloci 3 When the nail stops moving where did the energy go New From of Energy Heal Heat Was nut epnsrgereg a turrn pt energy unm tne rmdr mum s Pnprtp tnatrtyyastnpugnt at as same type at nurg tnat made tnmgs nut nfactneatenergy peauegtn justa ars errnar energy rs reaHy rnrerpseppre turrn pt Wyeth energy Thus vvnenvve epnyertenergy mm neatprtnerrnar Energy tne Wyeth energy rs nut seen astne net rnutrun ura arge Dbje We a e rura naH butmste g as an mcrease m tne yerperty pr rngryrguar partreres wrtn rangprn rnptrpn Srneetne rnutrun rs randum tne abjectdues nut appear tn rnuye butjust nas a nrgner temperature Temgerature rst grear grugumunar tn tne average Kmart E pr uamdes m a rnaten Npte tnattnerrnar energy can be narg tp use get at ur EDHVER mm ulnar farms Another Energy Mass Energy Over mu years agu Arpert Ernstern grseuyereg tnat rnass rsjus t anutner turrn pt energy 2 Ezmc rs rnass m k ugrams 5r Umts and e rstne speed at hgnt a gtlt1EE rnetersseepng Here rs rne E urmg Huvv rnuen energ up have Wergnt was ppungs cpnyertvyergntrn eartn s grayrtytp rnass 9 84 kg 1 2ch 84kgx3X108msz 58x10 8 Joules Cunsrdertnattne ermre USA uses WEIEI QEtu urWDZDJuures eaen year Tnustne energy m rny ppgy enurg run 3 tne ngnts tprza uutufSEE days m a year Huvveyerr m nuerearreaetmnsrwe surnetrrnes upserye tnat tnere Was a hma rnure rnass perure eurnpareg wrtn Nvards Frssrpn Reactmn Sphmng Fusmn Reactmn Aggrng Chker Questan I K39 Fission Energy Release U235 n 9 BaW Kr32 3n U235 n 9 Te 39 ZI 34 3n rtypu aggtne rnasses petpre and artery yuu nng tnatypu rust apputa gtlt1E7 3 Wugrams m tne prpeessr RecaHm tnatErne2Wnere e rnsrwnatrstne ratm pt energyrrprn 235 grarns pt Uramum m2 atprns eprnparegtptnattrprna t puund urnp prepar rumpuresw A Uramum and epar energres are abuut e a a Uranrurnenergyrs mun pttneepa e C Uranrurnenergyrs tuuutrrnestneepar energy D Uran u nergy rs mu nun trrnestne epar energy EUrmuummc2 10 x3x10 kg3xloxme2 10 J Nudear ssmn eham reactmns are Nudearvveapuns nuvv utmze bum ssmn and fusmn reactmns Chermea Reaeuuns Nude rrrvuwe amrme ahectruns ru ar Reaeuuns mvu ve Em and neutruns m the udeus Typma Energy per reacter 1EI S James Typma Energy per UM reacter 1EIMJUMES Dr 2mm Mev sun rs puvvered by fusmn reactmns m the cure The sunva untmue m bum fur a few when mere years befure u runs out uffue howls In me sum cums puulc Lung Llnls ll l l Wuleer TN onnu umvssnrt GDP ls denned as tne tutal marketvalue untrylna l p ldut tlrne typlually une year rue Wlklentry uf Arnenua ll Trllllurl Dullars per year Natlunal Dept a 5 Tnlllun Dullars Federal Budget 2 7 n Tnlllun Dullars Extra Credlt 4 Attend tne tururn beluvv and erte a une page paper un Wu speulnu sulentlnu pulnts tnat yuu tuund lnterestlng and check Wltn utner reterenues tnelr yalldlty COLORADOLAW Rernlnders Read Cnapter 3 ut tne textbuuk Rem Humevvurk 4 l5 pasted and due nextWednesday lndulrelnturrn Asslgnmentl due neXtFrlday uurne and talktu rne ltyuu naye duestluns Alternative Sources Oil Shale Desplte tne namey lt lS nut really Elll and nut really snale Hydruuarpun rnatenal lS usually kerugen Dldn t get cuullted lung enuugn tu aka ull Lacks sufflclerlt nydrugen tu make tne lungrchaln nydruuarpuns uf ull hm Www tu due guvpmglamsleselvesnplNPRLOlLShaleinglam nlml Mlcmwava my In exhacxml lmm spulu Tar Sand Ascous oil and sand mixture tar like substance bitumen Mine as a solid then process out the oil 2 tons of sand 9 gives one barrel of oil Found in Canada Northern Alberta Already some economical recovery is underway Total impact unclear at present Alberta Oil Sands mum ar Live w m Thermodynamics and Heat Engines 1 BTU is the energy to heat 1 lb of water by1 1 BTU 770 ftpounds This energy can lift 1 lb up 770 feet degree F This is about the chemical energy in one wooden match Lots of energy but how do we get at it Burning the match generates heat easy but how do we get it to do work turn a turbine or generate electricity How can we capture heat energy which is still energy and do useful work with it We use the symbol Q for heat energy Note it is just like any other form of energy with unit like Joules BTU etc Heat Engine Q hot Q cold Heat energy input Heat energy wasted Heat Engine From a hot From a cold reservoir Thut FeserVOiquot Tculd Work extracted Q hot Heat energy input Heat Engine From a hot reservoir Thut 1 Work extracted Q cold Heat energy wasted From a cold reservoir T culd 39 er Question Conservation of Energy tells us which ofthe following equations must be true A 0m work chld k B Qhm Wor C 0m chld work D QE id Wor E You cannot write an equation with Qheat and Wwork because they are not the same thing Energy is conserved Both Qheat and Wwork are forms of energy Thus the energy input must equal the total energy output A is the correct answer heat Elf cumbustiun is the maximum amuunt pt enernteat energy ayattapte an ts atyyays s tne tettat energy eetntent at any tnputmet Wurk tame QM Yuu ean neyer get mure it ts trnpetsstpte tet get em my and tnus Wurk lt QM atyyays Tnts rnean at setrne neat pt umbustiun energy ts atyyays unayattapte tet get Wurk Can neat tnerrnat Energy pe usemttpr gettng reat Wprw A we neattstne End pruductufenergy enatns it ts energy inst El the Envirunment 3 Nut neat represents randum gtsetrgantzeg mutiun and tneretetr ea rprud t Dr C Yes he e nye rnetttet t t t s neatenergy ts We any utherkind pt energy in Tne 2nd tayy pt Tnerrnetgynarntes pasteatty states tnat c ts eetrreet it CAN drive rnetttetn get usemtyyetrm butCamut snetyyeg the maximum yuu ean get ts ttrntteg pytne temperatures etttne seturees pt neat yuu n ye Wurk GM 7 GM Efficiency energy yuu putin One ean etnty aenteye munn Efficient eetnyerstetn pt neat energy tntet Wurk tt QM u Untetrtunatety tnts ytettates tne tayys pt tnerrnetgynarntes it eetrnes tretrn tne pnnetpte tnat ENTROF Y type at disurder pt mnett DEW Heat energy tnput Heat Heat energy Wasted Engine mm a net Frum a e reseryettrTM rEsENuirde Wurk extracted Tne seeetng iavy pt tnerrnetgynarntes teHs us tnattetr ANY neat engtnet uperattng thn any rnatertais tn any Way Temperature T nas an apsettute tetyyestyatue Apsettute Zeret Tne Ketytn temperature seate nas TEI at Apsettute Zeret Lard KEMH TKev 1 TCes s273 Thus absuiute zeru ts TCeistus 7273 C T Cetstus 53 X T Fahrenheit 7 32 tested and ean pe ungerstetetg tust py knuvving tnat eyerytntng t made at atetrns and the temperature ts retateg tn tne average kinetic energy uf tnese aturns Key The temgeratures ir written in units of Kelvin Tnus muF tun Dc pettitng Water 32 F u c treeztng Water 73 F 23 no mum temperature 7459 F 273 c apsettute zeret Tem gerature IS not the same as heat Heat reterstp the energy ln a matenal guetp tne rangpm s mptlpn klrlEtlE energy pttne atpms ang muleeu Temp tells yuu muleeule erature ls whatyuu measure vylth a thermumeter and lt apputtne ayerage energy pttne atpms and s EV2mv2 le Internal energy of air molecule at room temgerature T In DC 293 KEM Boltzmann Carlslam KE muleeules 1 5 k5 BxlEl 21mules Alrmgleeulesln1tt3 7 2x1u21 lnternal energy ln 1 n3 43EIEIJuulEs l How fast are these a molecules mo ng 2e k Massmpleeule EXlEI g KE 12my2 9velucltyv 4mm ms EDD mlles pernpurl Carl yuu get attnlszlauuupules utenergy and get lttp up wurw u atEEIEI mph lmaglne pullglng a plstpn ang trylng rature gas 1 e the same Tastne putslge alr Whatvvlllhappen Not mgwrllhaggenl Whatypu ean up lt add heat the gas As the gas temperature lncreases tne muleeules naye a larger klrlEtlE energy and thus a larger pressure an the Wall Tnustne uutvvard tpree myylll be greater than the lnyyarg tpree 6 0H The glston wlll m ov e eulsueen Gas dues Wurk an the plstpn Walk Fume x Dlstanee Wurk eumes trpm tne lnternal Energy and astne gas Expands Q the temperature geereases The prpeess stpps when lnslgeputslge egulllpnum reaeneg pptn back tn the same temperature Gas lnslge stlll nas lnternal Energy put We can t get at t vyltnput lpvyenng tne putslge alrtemperature eplg rEsENulr Thus you cannot extractwork from thethermal energy ofthe air in the great outdoors Reminders j UN Clouds of pollution threaten glaciers health V Reading Chapter in Hemewerx m a due Wednesday inquireintenn 2 due Wednesday lri eiass Extra CreditE dde Friday lri eiass Exam 3 detailsWill be given enWednesday arne exam is ill eiasstne Wednesday arterbreax Dee 3 Deadline ten changing research Epics lS tnis Friday ettne student nunurcude tn Sig a EffeCtS 0f NOX isitayiuiatiun n n attendance sneetrur a classy and tnen immediately ieaye Effects become noticeable at 15 ppm A Yes it is raiseiy asserting tnatyud are aetiyeiy participating in a eiasstnatyuu are nut 9 Irritation of eyes and lungs El thne signing unly signifiesthatyuu WErE present at s Dangerous at much lower concentration surne puirit ddnng tne eias than or C Nd because nu ullege eiasses snudid naye any part at grades based un partieipatiun Air quality standard is 0053 ppm Egegtu rt39naenneetxnaurr eude lS unly iryud direetiy piagianze ur No2 Hzoa HNO3 NimC Add NO is a greenhouse gas E Nd but it is nut very nice tn tne instrdetur and utner tddent Reducing NOE from cars Lower combustion temperature 9 Reduces ef ciency Catalytic converters Does not depend on type offuel or details of sign engine de and nine ll 5 and me him 1 5m Photochemical Smog N02su ht N00 o 02 03 03N0 N0202 Add unburned hydrocarbons H rocarbons react with NO to form awful stuff Thus NO concentration decreases Photochemical Smog N02 sunlight N0 0 o 02 03 03N0 rN02102 Reducing NO concentration decreases ozone destruction thus increases ozone concentration Result awful stuff 1 more ozone Photochemical Smog Pruducedfrum uox l l bllllvllll nlalll iisiiim ennui lilnlllelilli Catalytic converters Reduce Evaporation uffuels or lower eprnpustipn reguees these hydrocarbons temperature helps NO2 absorbs blue light Light passing through is missing blue and so looks redbrown an important component of sm http lViMANsmogch eckcagov Clicker Questiuns Whatare gppu iueastp help in pig eities like LpsAngeles7 A Laws reguiring sprne pereentage ufcleanefuel vehlcles 3 Allow hybrids and high occupancy vehlcles in speeial lanes c Farce pepple tn share riges nu pne intp the city Withuut passengers D Large investment in rnass transit E Enepurage pepple tn rhqu out at LA to reuuee pupulatlun Sulfur Dioxide Primary source is burning coal Most coal has at least some sulfur 1 Eastern United States coal has 3 Even 1 is a LOT of sulfur 1 of 10000 tonsday is nsday Sulfur Dioxide Combustion of sulfur s 02 a so2 really smelly stuff Hzoso2 a st03 sulfurous acid Then oxidized to sulfuric acid H2803 Problems start at shortterm exposure to 01 ppm Longer term exposure to 001 ppm my card MW mainly 39 V lmm mam namm lncmnmo m lncmnncn a mmwm l olsemn 3 m 3 WWW g l4 Rmmlm B 33213 2 in 5mm lmm 39 as aw w wanlbzzs 2 sl l mm was lppml Sulfur DlDdeE Natural Sulfur Hydrogen sul de HIS Decay product sulfates in ocean spray Aerosols with relatively short lifetime Similar quantity by volume but usually less serious in practice Atmosgheric Processes Sulfur dioxide combines with water vapor to produce Sulfuric acid Sulfur dioxide condenses on atmospheric particulates carried bythe wind for great distances Sulfur dioxide and sulfuric acid combine with carbonates and silicates to form watersoluble sulfates Effect on Buildings carbonates in marble converted to watersoluble sulfates black Thepollution in Athens s eroding the marble ofthe Parthenon Reducing Sulfur Dioxide Lowsulfur coal in Wyoming But less sulfur but less energy by weight so net decrease may be sm Atthe Wyurning State Museum We saw a display an huvv Wyurning is helping Wim pullutiun because er its cleaner eea Reducing Sulfur Dioxide Mimic atmospheric process in the smoke stack Spray exhaust with water 1 Converts 02 to H2803 sulfuric acid 2 Add limestone limestone calcium carbonate 3 Yields calcium sulfate water CO2 Exhaust is cold and must be reheated to rise Reguires 5 51 of the energy output Increases capital construction cost by10 n Waste Products Slurry consists of Calcium sulfate Sulfuric acid Water What to do with this stuff No good solution for dealing with acid slurry Older Generating Stations Should older plants be retro tted with scrubbers About 50 ofplants were built before 1975 Rates for electricity were set based on an assumption about station lifetime which is 1990 Clean Air Act By 2000 Reduce SO2 emission by 50 from 1990 levels New EPA rule in 2005 for Eastern states e emissions or buy allowances Red Emission limits based on generated ower Cleanest plants can sell allowances to dirtiest ones Clicker Questiun W By 2000 reduce SO2 emission by 50 from 1990 levels Should oldestdirtiest plants continue to operate A No they violate the Clean Air Act B Yes they should be allowed to buy allowances until they are modernized Other Solutions Real Progress in some areas mm mquot ml mm Rate mm I Acid Rain Sulfuric Acid from Sulfur Dioxide Nitric Acid from NOX What goes up comes down Somewhere else Prevailing winds carry material North and East eg Adirondack Lakes World Pupulaliun Gnath 39 lrough Hlslory a x mm 7 m New m Ag m smug M um m M a e Wm u u 9 A 755 s 339 w m 53 a e 1 1 g a 25mm ma mu m um 1m 2000 mm mm 5 M 3 ac ac c as m an ac AD no Wh do egtlt onermd funcuons often occur Whatare the 7 t uamy OCN At Often the rate of change of some o N 5 propomona to me quanmy N Can you mmk of some examp eg w you turn th me a dwffererma equauon and soNe m the semen 5 an exponenua N t expct fyou have never seen a dwffererma equauom do notworry Juat know that exponenua s occur 5 me We Lots of other examp es mtereat on money Wus nudear decay ANAt lt 0 Note that often there are correcuons e 9 amoeba 5 50 dwe at some ra te N t xpct Tnere is a very niee pucketfurmula tei rernernper Tne time for surnetning tei deiuple Duubllrlg Time is given it intlatiein is 3 5 neiw many years Will it take for priees tei deiuple7 A 3 5 years D E Human Popula on Problem pen it rain wen i 3 in Currently peipulatiein gruwm isi 2 it itteilleiws an expeinential and untlnues at tnis greiwtn ratei t e deiupling tirne 7n i 2 58 years Thusitne wurld s pupulatiuri wuuld be 12 billiuri iri ZEIBE If this growth rate continued for950 years the hum an population would grow to 500 trillion How big is soo trillion The entire surface area of the eanh is soo trillion square meters land and ocean Thatwould mean ne person per square meter Feeling crowded 0 Clearly something would happen well before then Aetuallyi tne rate eitpeipulatiein gruWIh nas peen sleiWing Tnis is Why preiieetieins at w en tne Wurld s peipulatiein WlH deiuple keep enanging and depend ein assurnptieins cu StudentPupulatiun U 39t Conver ns SEE inside jacket uver uttne EXIbDDk Example Wnat is in em centlrmeters in inenes2 Nutiee that the em cancel nut abuve Standard International SI Units mp invWthsics ntst gavcuuUnnscunem ntnt Si unit at energy Jggtet Si unit at puvver energyttrne Watt EDD Hurseggwer Autgrngbtie t D BTU Return Atr angtttgner BTU gr Btu Ertttsn Tnerrnai Untt vvna ts tne energy uutput tn units ut JuuiEs trgrn burning i puund ib gtegaw Tabie 2 B says tnattne best egat Antnraette wnten ts 88 arbun nas an energy untentufiS SDD Btuib l KEIEIBtu E em a1 7 nergy cu x Mm 133IEI Btu Next Week we WiH gtsegss gtnerent units at energ t Fur nuvv nette tnat Eitu ang Junie are butn units at energy Bunk tnstge jacket says 1 Junie a 43 X in 4 Eitu lJuule Ener 133nn Btux gy 949x1u Bt Order of mag ude est mates OOML Often we want a quick answer tnat gtyes us tne an appruximate seaie gttne prubiern in tnts case we are nuttnteresteg tn betng accurate wttntn a taetgr at 2 gr at but uniy being aeegrate wtntn a taetgr at ten surnettrnes eatteg an grgergt magnitude taetgrgt ng rnanytetty beans are tn tntstar7 a Vuiurne at at a Jar Size stngte tetty bean Packing traettgnt Exampie Tne energy trgrn etne puund uf egat ean run an an Watt itgntbuib tgrngw igng7 irnpgrtant ngte nergy ttrne uuies seegng Si Untts Watts iib ufcuai nas i 4 X iD7Juuies ang tne itgntbuib uses an JuuiEssecund COM 7 rgung aii numbers ufftu tne nearestfactgr gt mt Time a 1 Energy used by lightbulb pet time 100 Joulessecond Time Rs 105 seconds 105 seconds sounds like a big number As an Orger uf Magnitude esttrnatet ngw rnany gays ts tnts7 get nutuse a eategtatert A u m ga s E01 ugays ays D iEIEI u gays E Ngne gttne abuve Ttme1n5seex 1mm x H x mi n see mm zAheturs TimewlUSSEEXEImm M may jatgaytoowt l se lEIEImm l huurs Homework 1 is due TODAY Wednesday January 21 at 5 PM CAPA server will automatically record all correct answers entered by that time No late homework accepted Last 3070 TA Zack in Help Room 34 PM today Question 5 help at end of lecture If you added the course after last Monday use the CAPA late enrollment page phys3070 page gt Homework gt CAPA gt Homework 2 paper copies will be in bins amp will be active on CAPA by 530 PM today The course web page is httpwwwcoloradoeduphysicsphys3070 Syllabus on the web page will be modified Clicker Question 105 seconds sounds like a big number As an Order of Magnitude estimate how many days is this do not use a calculator A 001 days B 10 days C 100 days D 1000 days E None of the above Time105secx1mm x lhour x lday 60 sec 60 min 24 hours Time 105 sec x 1mm x lhou x lday 1dayOOM 100 sec 100 mm 10 hours With 300 million cars how much gas do they use What is the mileage driven per car per year Estimate 15000 miles per year What is the miles per gallon MPG on the average car Estimate 20 MPG Miles Driven X Gallons of Gas GaHOHS carsx Car Mile Driven l Gallons 3 x 108 carsgtlt 15 x104m11escar x 20 MPG Gallons z 108 x 104 x 10391 1011 Gallons of Gasoline 100 billion gallons of gasoline each year Example The energy from one pound of coal can run an 80 Watt lightbulb for how long Important note Power energy time Watts Joulessecond Sl Units 1 lb of coal has 14 x 107 Joules and the lightbulb uses 80 Joulessecond COM round all numbers off to the nearest factor of 10 Energy from Coal 107 Joules Tim z Energy used by lightbulb per time 100 J oules second 5 T1me z 10 seconds More involved example as a way of thinking How much money is spent in the USA on gas for cars each year This is relevant for gas standards gas tax How can we estimate this without detailed information Perhaps start with how many people in the USA Estimate 300 Million could check from US Census How many cars per person Estimate 1 car person So we have 300 million cars in the USA l Gallons 3 gtlt108 carsgtlt 15 gtlt104n1ilescargtlt 20 MPG Gallons 108 x 104 gtlt10391 1011 Gallons of Gasoline 100 billion gallons of gasoline each year Even for a rough estimate we might do better keeping the most significant digit And it is not much extra work Gallons3x108x 2x104xlx1039l 2 Gallons32gtlt108 gtlt104 xlO39l Gallons z 3 X1011 Improved Estimate 300 billion gallons of gasoline each year The question was How much money is spent in the USA on gas for cars each year r I I I I I I I I I I I I O O Ja an Norwa So for these 3x1011 gallons of gas we only need to know the p y Switzerland UnIted States average prIce people paId per gallon of gas 30000 Iceland B OSweden This is from around 1998 Has the price of g U K 5quot1any c ad i u 39 an a gasoIIne changes sInce then J 2039000 Be39g39m 9 Italy THIS SALE u Estimate Roughly 200 per gallon quot GALLONS E 2 Cuba So roughly 600 billion dollars are spent quotTEcuador Poland 39 on gasoline per year 0 N 39I 39 I I I I I I I 0 10 20 30 40 50 60 70 Barrels of oilcapita Figure 13 Energy and the Environment 2e One can look up the real numbers at zooaohnwneys50mnc National Transportation Safety Board httpwwwntsbgov They estimate US uses 200 billion gallons of gas per year Elichw ork Eimcs Bu si ness tInIRLII 113 NJquot REGIorI BUSHJESS TECI II39JIIIIILCZIGY SCIENCE HEALTH SPORTS CIPIranjrr lIJlEEIle39l EJ v ERTlfIzlhlti IIIroFILEi EIII3IIIE I IZZIILIRrI1IIIIIP1E I IIE39lLEIIiIIIIIZZIHI IvIAFIItETs CIIIIIIP3IIquotI RESEL39IRCH MU Home Finance Center 143317 If i IZII IIII II I SCH l39 32 icitl39 iI39iICIlS iI l39 vIcI am lIijl WL39It J ECONOMIX What 12 Trillion Can Buy a I 0am Lemmanor H Published January i7 JJU EmiliaIL The human mind isn t very well equipped to make sense of a figure like I31 F39FIII IT 12 trillion We don t deal with a trillion of anything in our daily lives E REPRINTS 39 H and so when we come across such a big number it is hard to f 3gtE V i 2 quot distinguish it from any other big number Millions billions a trillion E3 SH g39RE if f quot Aquot 39 39 i 39 theirallstarttosoundthesame People use an enormous amount of energy each year 400 QBtu The way to come to grips with 12 39CHEn 7 mummedia trillion is to forget about the number 39 1 m m user and think Instead about what you People In the U SA use about A of the total 1 00 Q Btu 339quot preschool 5 0 3 and could buy w1th the money 39When you do that a trillion We mm stops sounding anything like millions or billions But what exactly I n physIcs terms Is energy 333333333 33933quot For starters 12 trillion would pay for an unprecedented 200 billion 35 billion I L Gram public health campaign a doubling of cancer research A d h d k h t I I t putting the Annual Cost Ufwar funding treatment for every American whose diabetes or n O n W a a S m a a m 0 u n u S a n e n O O u S in PBI SP39ECfi f heart disease is now going unmanaged and a global a m 0 u e n e y Etymology edit A A Work Force x DIstance F d The etymology of the term is from Greek Look up Energy in EV PlEIOI V means quotInquot aIId PlOV means Wiktionary the free dictionary quotworkquot the a suffix forms an abstract noun ThlS IS the deflnlthn In terms Of forces as SpGleled The compound avepyaa in Epic Greek meant quotdivine actionquot or quotmagical operationquot it was Isaac Newton e Force mass X aCCeIeration F later used by Aristotle in a meaning of quotactivity operationquot or quotvigourquot and by Diodorus Siculus for quotforce of an enginequot Direction quot of movement PhysIcs DefInItIon J as result of force Energy is the capacity to do work How much energy you have tells you the amount of work you d can do in principle 1 So what is work BIClicker Questions Energy is the key to everything However often energy in different forms appears very different to us This person pushes the curling rock of mass 20 kg and releases it with a velocity v 3 meterssecond 1 Kinetic Energy energy of motion 33931 What is the kinetic energy ofthe rock K E my2 A 30 Joules B 60 Joules N 2 C 90 Joules D 180 Joules 39 E 320 Joules where m mass ofthe object in kilograms and v velocity of the object in meterssecond 1 21 2 KE m 203 2v 2 Since energy is conserved how much work has the person done in pushing the rock from rest to this velocity A 30 Joules B 60 Joules C 90 Joules D 180 Joules E 320 Joules Note that the maximum mass of a rock is 1996 kg http enwikipediaorgwikiCurling Enerqv is conserved A A39 The exact amount of energy the entire universe started out work Force dlstance with 14 billion years ago is exactly the same amount of energy the universe has today lfyou hold a weight xed there is no change in position d0 and so zero work is done The same if you push against a wall Counterintuitive it is not the English language usage but It is well de ned in physics terms and very useful In our curling example once she released the rock is she doing any more work In the absence of friction the rock would continue at the same velocity forever At least according to our laws of physics We always talk about using energy so how can energy be conserved It turns out we are always just changing one form of energy into another Sometimes the new form of energy is less useful Many different forms of energy but they are all energy nonetheless We have already introduced kinetic energy and now we will list many other important categories Note that energy conservation in everyday use means using less energy like turning off the lights Not the same as our physics meaning in which energy is conserved for every process in the universe Demonstration with tennis ball and spring At the beginning the tennis ball has kinetic energy KE 0 Joules After pulling the clip the tennis ball goes ying across the room with some velocity Since energy is conserved where did the energy come from to give the ball this kinetic energy When the ball finally lands and stops moving where did the energy go Another Example Gravitational Potential Energy PEUmgh where m mass g 98 ms2 and h height above the earth s surface F Using a force F we lift a book off the ground by a height h The work energy is now stored as gravitational potential energy If we drop the book it accelerated due to gravity ie converting the potential energy into kinetic energy motion Our second form of energy is stored energy not associated with any kind of motion 2 Potential Energy Example spring potential energy 1 PEUEkAx2 Where k spring constant and Ax is the displacement of the spring from its relaxed length Note that we must have done work Force x distance in the first place to store this energy CAPA Question 5 HELP Thought extra needed equation was in book it isn t Gravitational potential energy mgh at beginning t0 becoming kinetic energy 12 m v2 at solution time t just when it hits ground needs ignoring air resistance amp additional equation For constant acceleration we have dvdt a Cg where C is a constant and g98 msec2 lgnoring air resistance amp close to the earth s surface C1 unless there s another source of acceleration Simple integration Av vf vi CgAt Cgtf ti lfvi 0 at ti 0 then vf Cgtf Should finish reading Chapter 1 27 pages start in on Chapter 2 this week