Results 1 to 2 of 2

Math Help - Newton's law of cooling question/problem

  1. #1
    Newbie
    Joined
    Jul 2010
    Posts
    18

    Newton's law of cooling question/problem

    An object was cooled to 28 Degrees farenheit.
    It was removed from cooling and was taken into an environment of 70 Degrees farenheit.
    After 10 minutes its Temperature raised to 35 Degrees farenheit.
    What will its temp be after 30 Minutes

    Formula: U(t)=t + (U0 - t)e^kt

    Please help me
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor

    Joined
    Apr 2005
    Posts
    15,372
    Thanks
    1314
    Quote Originally Posted by IneeedHelp View Post
    An object was cooled to 28 Degrees farenheit.
    It was removed from cooling and was taken into an environment of 70 Degrees farenheit.
    After 10 minutes its Temperature raised to 35 Degrees farenheit.
    What will its temp be after 30 Minutes

    Formula: U(t)=t + (U0 - t)e^kt

    Please help me
    First, your formula is wrong. At least one of the "t" should be "T", the temperature of the environment, 70 degrees, while at least one should be "t" the time after the object is removed from cooling.

    If I am reading this correctly, your formula should be U(t)= T+ (U0- T)e^{kt} where "T" is 70 and "t" is the number of minutes after the object is removed from cooling.

    At t= 0, when the object is first taken out of cooling, U(0)= 28 so [tex]28= 70+ (U0- 70)e^{k(0)}= 70+ (U0- 70)= U0. That tells you what U0 is.

    At t= 10, 10 minutes after being taken out of cooling U(10)= 70+ (U0- 70)e^{10k}= 35. You already know U0 so you can solve that for k (you will need to use a logarithm).

    Finally, after you know U0 and k, evaluate U(30)= 70+ (U0- 70)e^{30k}
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 1
    Last Post: March 10th 2010, 02:51 AM
  2. Newton's Law of Cooling Question
    Posted in the Calculus Forum
    Replies: 1
    Last Post: December 18th 2008, 06:31 PM
  3. Newton's Law of Cooling Problem--help please
    Posted in the Calculus Forum
    Replies: 1
    Last Post: April 28th 2008, 09:02 AM
  4. help with DE problem: Newton's law of cooling
    Posted in the Calculus Forum
    Replies: 2
    Last Post: January 22nd 2008, 03:20 PM
  5. Newton's Law of Cooling problem
    Posted in the Calculus Forum
    Replies: 1
    Last Post: May 17th 2007, 10:53 AM

Search Tags


/mathhelpforum @mathhelpforum