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Suppose a human could live for two hours (120 minutes ) unclothes in a

  1. Nov 14, 2013 #1
    Suppose a human could live for two hours (120 minutes ) unclothes in air at 45 F . How long could he live in water at 45 F ?

    how do the thermal conductivities of water and air compare ?
    Air : k = 0.0251 W/mC ,
    water = k = 0.597 W/mC


    my answer

    now for conduction we will say that

    -k(air ) .A(dT/dx) dtime = -k(water ) .A(dT/dx) dtw

    = 0.025 X 2 / 0.597

    = 0.083 second
     
  2. jcsd
  3. Nov 14, 2013 #2

    Borek

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    Staff: Mentor

    Huh?

    No idea what is what of what nor how you got the number you got.

    What is 2?

    And your math is incredibly off.
     
  4. Nov 14, 2013 #3
    sorry

    = 0.025 X 120 / 0.597

    = 5.04
     
  5. Nov 14, 2013 #4

    Borek

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    Staff: Mentor

    That looks much more palatable.

    It won't hurt to include units in your answer.
     
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