X3.18a 1070PHYS-1070(18) (Kaldon-20592) Name _______ __S O L U T I O N__ ____________WMU - Summer I 2006 Remember Your Paper!Exam 3 - 100,000 points Rev. 06/15/06 Th.2State Any Assumptions You Need To Make – Show All Work – Circle Any Final AnswersUse Your Time Wisely – Work on What You Can – Be Sure to Write Down EquationsShort Answers Should Be Short! – Feel Free to Ask Any QuestionsEXAM 3 [FORM - A]PHYS-1070 (KALDON-18)SUMMER I 2006WMU“I wanna be a firemanwhen I grow up.”Physics 107 / Exam 3 [Form-A] Summer I 2006 Page 2“Fact or Fraction” (30,000 points) Multiple-Guess-Pick-The-Best-Answer-Fill-In-The-Bubbles1.) (a) Refilling a half-empty water tower is designed to increase the __________ Pressure.A = Absolute B = Gauge C = Potential D = Kinetic(b) When you open a bottle of champagne, you hear a pop, meaning that the __________ Pressure is positive.A = Absolute B = Gauge C = Potential D = Kinetic(c) Both the __________ Pressure…A = Absolute B = Gauge C = Potential D = Kinetic(d) … and the __________ Pressure must always be a positive number.A = Absolute B = Gauge C = Potential D = KineticIn parts (e)-(g), select which of the laws and definitions of Thermodynamics is best used to solve or describe theproblem.(e) The Carnot Efficiency is zero when the hot and cold reservoirs are in thermal ______________.A = Thermo 1st law B = Thermo 2nd law C = EquilibriumD = Actual Efficiency E = Carnot Efficiency F = None of these(f) Second Law Efficiency is a measure of the fraction of the _____________ that a heat engine achieves.A = Thermo 1st law B = Thermo 2nd law C = EquilibriumD = Actual Efficiency E = Carnot Efficiency F = None of these(g) The waste heat rejected cannot be zero as a consequence of the ____________.A = Thermo 1st law B = Thermo 2nd law C = EquilibriumD = Actual Efficiency E = Carnot Efficiency F = None of theseThe following regards boats floating in water.(h) The density of the material the boat is made out of is always ___________ than the water.A = Larger B = Smaller C = The Same D = None of theseThe material of the boat is irrelevant, only mass/volume.(i) The volume of the boat is __________ than the volume of the water displaced by the boat.A = Larger B = Smaller C = The Same D = None of these(j) The mass of the boat is __________ than the mass of the water displaced by the boat.A = Larger B = Smaller C = The Same D = None of these! " f $ % &! e # $ % &d " # $ % &! " # g % &! " f $ % &! " # $ h &! e # $ % &! " # g % &d " # $ % &! " f $ % &Physics 107 / Exam 3 [Form-A] Summer I 2006 Page 3“Engine Company 107, Time Out, 15:48.” “Roger.” (35,000 points)2.) (a) The fire truck’s horn goes BLA-AAT! with afrequency f = 50.0 Hz. If the horn consists of a tube openat one end and closed at the other, how long L should thistube be? The speed of sound in air is 345 m/s.For a tube open at one ends and closed at the other…The Fundamental is one-quarter of a wave(anti-nodes at one end, node at other).vfvfmsHzmLmm=== === =lll34550 069004690041725/....(b) The water tank in the fire truck is pressurized to gauge pressure of 147 psi (10 atmospheres = 1,013,000 Pa).The pressure outside is the normal atmospheric pressure of 1 atmosphere = 101,300 Pa = 14.7 psi. What is thespeed of the water coming out of the fireman’s hose? Assume no height difference between the nozzle and thetank. rwater = 1000 kg/m³Pgh vPgh vPP vPP vvPPvPPPakg mms11121222122212122212122222122123222 1 013 000100045 01++ =+ +=+-==-=-==rr rrrrrrbgbgbg,,/./Physics 107 / Exam 3 [Form-A] Summer I 2006 Page 4(c) What height for a open column of water in a water tower would give the same gauge pressure of 147 psi (10atmospheres = 1,013,000 Pa)?PghhPgPakg m m sm====rr1 013 0001000 9 81103 332,,/./.chch(d) There isn’t enough 3 inch hose to get the water close enough to the fire, so they have to splice in a section of1 inch hose in between two pieces of 3 inch hose. What is the speed of the water in the 1 inch section of hose?1 inch = 0.0254 m. If you didn’t get an answer to part (b), use v1 = 25.0 m/s.Av AvvAvADvDDvDmmsmms ms11 2 21221422241222212223 0 0254 45 010025494501 4051=== ====pp../../ ./bgchbgbgbg(e) In the fuel tank of the fire truck, a small float goes up and down to let you know how full (or empty) yourfuel tank is, sort of like the float in the tank of the toilet in your bathroom. Suppose that a fuel tank float hasdimensions 1.00 cm × 1.00 cm × 0.300 cm (0.0100 m × 0.0100 m × 0.00300 m). Find the mass of this fueltank float, if it is exactly half-submerged in the diesel fuel? rdiesel = 820. kg/m³Vmmmmkg m kg mmVmV kgm mkg kgboat diesel==´== ==== ´==´---0 0100 0 0100 0 003003000 10820 410 0410 0 3 000 100 0001230 1230 10731212333734...../ . /./ ...bgbgb gchchc hrrrrPhysics 107 / Exam 3 [Form-A] Summer I 2006 Page 5Eight Hundred Horsepower’s Worth of Fire Truck Power (35,000 points)3.) (a) The cast iron engine block of the fire truck in Problem 1 is roughly 0.800 m × 0.600 m × 0.400 m whenthe engine is cold, T = 68°F = 20°C. Find the volume of the engine when cold, and then when it warms toT = 450°F = 232°C. airon = 12.0 × 10 -6 °C-1bab== ´ = ´====´ -=+=+=+=-- ----3312010 360100800 0600 0400 0192036 0 10 01920 232 200 00146501920 0 0014650193561 6103061 330333..... .(. )(. )( )....oooooCCV mmm mVVTCmCCmVV VmmmchbgbgbgDDDIf the engine generates a useful power of 800. hp at full throttle, then there are 597,000 J of useful workgenerated every second. If the Actual Efficiency is 51.3% (0.513), then find (b) the total energy input, QH, …eeActualHHActualWQQWJJ====597 00005131164 000,.,,… and (c) waste heat rejected, QC, this engine accounts for each second?QWQQQWJJJHCCH=+=-=-=1164 000 597 000567 000,, ,,Physics 107 / Exam 3 [Form-A] Summer I 2006 Page 6(d) This engine has TC = 95°C and TH = 723 °C. Find the Carnot Efficiency of this engine.TCKTCKTTKKCHCarnotCH=°==°==- =-=95 368723 9961136899606305e.(e) Once a Cold Reservoir is established for this heat engine in the radiator, what would be the net heat flow inor out of the reservoir? Why? (Short Answer) Hint: You might ask yourself what is the one important thingabout a Reservoir.Zero.The temperature of a Reservoir issupposed to remain essentially constant over time.So the heat flow in and out have to be the same,therefore zero net heat