At 1:00 pm one winter afternoon, there is a power
failure at your house in Wisconsin, and your heat does not work
without electricity. When the power goes out, it is
F in your
house. At 9:00 pm, it is F
in the house, and you notice
that it is F outside.
(a) Assume that the temperature inside your home, measured in degrees Fahrenheit, is related to the temperature outside by Newton’s law of cooling. Express this relation as a differential equation. Let t denote time, measured in hours.
Use k for any constant of proportionality in
your equation; your equation may involve T and the values
in the problem.
(b)
Solve the differential equation to estimate the temperature in the
house when you get up at 8:00 am the next morning.
Temperature =
deg. F.
(c) The water pipes inside the house are well insulated from the outside, so their temperature depends only on the air temperature inside. Should you worry about these pipes freezing during the night?
(d) In your answers to parts (a) and (b), what assumption did you make about the temperature outside?
(e) What effect does this assumption have on the amount of cooling predicted by your model?
You can earn partial credit on this problem.