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hysics2020 Summer' 2013 Richard Ingebrctscn1 . J K . < I ' I I ~ ~ , j / I f ~ ' W o ( 1iIiItHIJI. rc:-.- " C .............B. [6 pts.} Supposethattheresistancebetweenthewallsof abiologicalcellis6.00 x 109n. Thepotential (differencebetweenthewalls is 135 mY. If thecurrentiscomposedofNa+ions (q "" +e),howmanysuchionsflowin0.5s?qf(.= 0 0 x/on.. VLJt= .t3S lV R.ebt:: 0-5/> T__ (i35Xii})(O5) - 1 O'Z'"5X1.0{'.GOIID"J(1 /'OZ.;,O")

c. [6 pts.} Awirehasaresistanceof 19.1 n. Itis melteddown,andfromthesamevolume ofmetalanewwireismadethat is twotimeslongerthantheoriginalwire.What is theresistanceof thenewwire?Ro:: IqUl R fL ~ fl. ::;: f(2.Lo) ~ w t .. V VDA A - ~ ( Z L o ) A ;:Lo" O ~ t W ~ V= Vo R =f (2l..o) ~ A ::::L':'. .2.Lo *,tt,QJ JtJajH. 0Lo (At>r;.."\AI>:: O ~ t l a . l eo::: .)A;: ~ r J lbyft. Ao ~ R = q.( ~ ) ~ Lf{ ~ )v I) ' N l I ~u .. /t:. .... 1JuUJIkl ~ f2.:: 41?-0 -:: t ( l ~ . J . ] n . ::: 1t>' 2/-fL_D. [6 pts.} Twocapacitorsareconnectedinparallelacrosstheterminalsofa battery.Onehasacapacitance of2.0 Jandtheotheracapacitanceof 4.0JlF. Thesetwocapacitorstogetherstore5.50 x 10.5Cof charge. Whatis the

voltageof thebattery? ( .... _ _ 2,'OOIol:r-t'f#= bfl-F'c,.20l-tf C1 C1.- - ~

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h ~ sics 202U SlIIllll1CI 20 L Richard Ingdu ctscn.

Name: J o s ~ Exam 3nid: _Discussion TA: 2A. [7 pts.] A resistor is connected across the tenninals of a 6.00-V battery, which delivers 3.60 x 105 J of energy to

the resistor in 4 hours. What is the resistance of the resistor? 1/:- ~ t? 7VP_ -L P: C _ 1t.{)>f -+) C-l?h/)y ,. :/.

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B. [9 pts.] A space traveler moving at a speed of 0.59c with respect to the earth makes a trip to a distant star that isstationary relative to the earth. He measures the length of this trip to be 8.0 light-years. What would be the lengthof this same trip (in light-years) as measured by a traveler moving at a speed of 0.85c with respect to the earth?

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~ L4 L, If) OL ) Eiif- :: t; lLLt, Y , Y . i _- 11:0,;/c. [9 pts.] Three resisto are conM:cted in series across a battery. The value of each resistance and its maximumpower rating are as follows: 19 n and 39 W, 116 n and 91 W, and 29 n and 4.9 W. What is the greatest powerthat the battery can deliver to the circuit without one of the resistors burning up? R : Itftq I : I{ I ~ t = , fl .t J f, 31

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Physics2020 Summer2013 Richat+d Ingebretsen

Name:Unid:_ _ _ _ _ _ _ _ _ _ _ _ C _ Exam3DiscussionTA: ---'-\4j---"-l-'hL..:'O:....::If\-=-- _ _ _ _ _ _ _ 3A. [9pts.] A1.05nresistorisconnectedacrossa7.60Vbattery. Thevoltagebetweentheterminalsof thebatteryisobservedtobeonly6.80V. Findtheinternalresistanceofthebattery.

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~ sics 2020 Summer 2 13 Richanl Ingelnctseniot

Name: _Unid: _ Exam 3Discussion TA: J q ~ G t = W : . . L l - I . - - - - - - - - _ 4A. [8 pts } A carpenter on a space station has constructed a 37.0 ramp as shown. A rocketmoves past the space station with a relative speed of 0.880c n a direction parallel to yside y. What does a person aboard the rocket measure for the angle of the ramp?

f::; l :::: 2. OS-JJ: J, S ; . xI . _ yoX = {\o r;;;:;-3 7yl= Ie:,r

B. [ 7 pts } Given the circuit shown. All capacitors are fully charged. How much energy is stored by the12.0 capacitor? 2 JJ F

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