Question

If you had to add cream to your coffee, when is the best time to add it so that you have the warmest possible coffee after 15 minutes?

Answer 1

@TheSmartOne

Answer 2

:oo Don't know, never drank coffee :p

Answer 3

lol is a physics class question

Answer 4

Assuming the cream is colder than room temperature, say at 5 deg. C and possibly maintained at that temperature during the 15 minutes, and the coffee is hot (say at 95 deg.C), then I suggest the following:
Assuming Newton's law of (forced convection) cooling applies, cooling rate is proportional to the difference between the room temperature and the liquid temperature.
If the cream has the same temperature now and in 15 minutes, then we're better off adding now, to cool the coffee down to 90 degrees, say, to reduce cooling loss in the next 15 minutes.
If the cream is not refrigerated, it "may be" better to add it later, because then the cream gets warmed up to room temperature before it cools the coffee. You may need to do a little calorimetric calculations to confirm which is a better choice.

Answer 5

As usual thank you so much for your help :)

Answer 6

You're welcome! :)