Results 1 to 3 of 3

Math Help - Half-life

  1. #1
    Member
    Joined
    Oct 2008
    Posts
    124

    Half-life

    The half-life of radioactive strontium-90 is approximately 29 years. In 1963, radioactive strontium-90 was released into the atmosphere during testing of nuclear weapons, and was absorbed into people's bones. How many years does it take until only 7 percent of the original amount absorbed remains?
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Grand Panjandrum
    Joined
    Nov 2005
    From
    someplace
    Posts
    14,972
    Thanks
    4
    Quote Originally Posted by noles2188 View Post
    The half-life of radioactive strontium-90 is approximately 29 years. In 1963, radioactive strontium-90 was released into the atmosphere during testing of nuclear weapons, and was absorbed into people's bones. How many years does it take until only 7 percent of the original amount absorbed remains?
    The fraction remaining after t years is 2^{-t/29}, so you need to solve:

    0.07= 2^{-t/29}

    CB
    Follow Math Help Forum on Facebook and Google+

  3. #3
    MHF Contributor

    Joined
    Apr 2005
    Posts
    15,792
    Thanks
    1532
    I would have written it \left( \frac{1}{2} \right)^{\frac{t}{29}} = 0.07 but that's exactly the same thing.
    Last edited by mr fantastic; September 1st 2009 at 04:28 AM. Reason: Fixed a latex tag. And the latex.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Half Life
    Posted in the Algebra Forum
    Replies: 2
    Last Post: May 11th 2009, 11:30 AM
  2. Half life
    Posted in the Calculus Forum
    Replies: 6
    Last Post: May 2nd 2009, 05:10 PM
  3. Half-life
    Posted in the Calculus Forum
    Replies: 1
    Last Post: October 2nd 2008, 12:24 PM
  4. half life
    Posted in the Calculus Forum
    Replies: 3
    Last Post: September 3rd 2007, 09:32 PM
  5. Half-life
    Posted in the Calculus Forum
    Replies: 1
    Last Post: May 29th 2007, 03:51 PM

Search Tags


/mathhelpforum @mathhelpforum