On 2011-09-24, at 5:36 PM, cdb wrote:

> You pour equal quantities of hot tea into identical cups.
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> After pouring cold milk into cup A, the phone rings. You chat for two=20
> minutes then pour the same quantity of equally cold milk into cup B.
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> Which cup is now hotter, or are they the same?
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> (I got this off the ABC website).
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> Colin

Cup A will be hotter.

Newton's law of cooling states that the rate of heat loss of a body is prop=
ortional to the difference in temperatures between the body and its surroun=
dings. Cup B, being hotter initially and therefore have a greater heat diff=
erence, will transfer more energy (heat) to the surrounding than cup A for =
a given period. Once the milk is subsequently added, cup B will be cooler.



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