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

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A discussion explores how long a human could survive in water at 45°F compared to air at the same temperature, given their thermal conductivities. The thermal conductivity of air is significantly lower than that of water, leading to different heat loss rates. Initial calculations suggested a survival time of 0.083 seconds in water, which was quickly corrected to 5.04 seconds after clarifying the formula used. Participants emphasized the importance of including units in calculations for clarity. The conversation highlights the critical differences in heat transfer between air and water.
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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
 
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manal950 said:
= 0.025 X 2 / 0.597

= 0.083 second

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.
 
sorry

= 0.025 X 120 / 0.597

= 5.04
 
That looks much more palatable.

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