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Unformatted text preview: = 998 kg/m 3 , and C p = 4.182 kJ/kg. ° C (Table A9). Analysis The characteristic length and Biot number for the glass of milk are 1 . > 076 . 2 ) C W/m. 607 . ( ) m 0105 . )( C . W/m 120 ( m 01050 . m) 03 . ( 2 + m) m)(0.07 03 . ( 2 m) 07 . ( m) 03 . ( 2 2 2 2 2 2 2 = ° ° = = = = + = = k hL Bi r L r L r A V L c o o o s c π ππ For the reason explained above we can use the lumped system analysis to determine how long it will take for the milk to warm up to 38 ° C: min 5.8 s 348 = = ⎯→ ⎯ = − − ⎯→ ⎯ = − − = ° ° = = = − − ∞ ∞ t e e T T T t T L C h V C hA b t bt i c p p s ) s 002738 . ( 13 21 60 3 60 38 ) ( s 002738 . m) C)(0.0105 J/kg. 4182 )( kg/m (998 C . W/m 120 ρρ Therefore, it will take about 6 minutes to warm the milk from 3 to 38 ° C. 46...
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This note was uploaded on 01/19/2012 for the course PHY 4803 taught by Professor Dr.danielarenas during the Fall '10 term at UNF.
 Fall '10
 Dr.DanielArenas
 Thermodynamics, Mass, Heat

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