From: utzoo!decvax!duke!harpo!npoiv!npois!houxm!houxa!houxi!houxz!ihnp4!ihuxr!lew
Newsgroups: net.physics
Title: Last of the tea discussion?
Article-I.D.: ihuxr.279
Posted: Sat Jan  8 20:36:36 1983
Received: Mon Jan 10 01:12:54 1983

Jeff Halle stated:

"Adding the cream will reduce the temperature of the tea by the same
amount whenever it is added. That is, the temperature will drop by
x degrees, not by x%."

The error of this assertion is obvious if one considers the limiting
case when the tea is nearly at room temperature. I'm sure most readers
know that the final temperature is the weighted average of the initial
temperatures, the weights being the heat capacities. This is just energy
conservation:

	Ca*Ta + Cb*Tb = (Ca + Cb)*Ta+b

Lew Mammel, Jr. ihuxr!lew