exam_I_2008_Cover

# exam_I_2008_Cover - || d(Q infil β t =(0.018 Btu/ft 3.F o...

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P110/120 Exam I DRAFT: subject to change!! 2 Oct. 2008 (1?? points) This is a closed-book, closed-notes exam. Some of the information you will need is given below. Some conversion factors, equations, and physical parameters that you might find useful: 1Btu = 1055 J : 1 cal = 4.186 J : 1 hp = 746 W : 1 ft.lb = 1.356 J g= 9.8 m/s 2 Properties of water: density: 1000 kg/m 3 Specific heat = 4186 J/kg.K =4.186 kJ/kg.K, Latent Heat of Fusion = 334 kJ/kg, Latent Heat of Vaporization = 2260 kJ/kg 1 jelly doughnut has an energy content of roughly 1 MJ. 1 barrel of oil has an energy content of roughly 6.12x10 9 J 1 ton of bitunminous coal has an energy content of roughly 2.5x10 7 Btu 10 6 cu.ft. of natural gas has an energy content of roughly 1.05x10 12 J 1 gal of gasoline has an energy content of roughly 1.24x10 5 Btu 1 Btu = 1055 J Useful Equations: KE = ½ mv 2 : PE = mgh : F = m a (Q/ t) = k (A/L) T = (A/R) T : W = F
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Unformatted text preview: || d : (Q infil / β t) = (0.018 Btu/ft 3 .F o ) V K β T W + Q = β ( PE + KE + TE) : Ξ· = 1 β (Q C /Q H ) < 1 β (T C /T H ) =: Ξ· Carnot T (Kelvin) = T( o C) + 273.15 K P = ΟΞ΅ AT 4 ( Ο = 5.67x10-8 W/m 2 .K 4 ) : Ξ» peak T = 2.898 mm.K Useful Prefixes: E (exa) 10 18 : P (Peta) 10 15 : T (tera) 10 12 : G (giga) 10 9 : M (mega) 10 6 : k (kilo) 10 3 m (milli) 10-3 : ΞΌ (micro) 10-6 : n (nano) 10-9 Some R values of importance: Fiberglass insulation (3.5βthick) R = 10.9 ft 2 .h. o F/Btu Plywood (0.75β thick) R = 0.93 ft 2 .h. o F/Btu Sheetrock (1/2β thick) R = 0.45 ft 2 .h. o F/Btu Wood siding (1/2β thick) R = 0.81 ft 2 .h. o F/Btu Hardwood floor (3/4β thick) R = 0.69 ft 2 .h. o F/Btu Asphalt roofing Shingles R = 0.44 ft 2 .h. o F/Btu Single pane window R = 0.88 ft 2 .h. o F/Btu Double pane window (1/2β gap) R = 1.72 ft 2 .h. o F/Btu...
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