Results 1 to 2 of 2

Thread: long question, help needed!

  1. #1
    Nov 2008

    long question, help needed!

    This is a long question whilch i think involves the quadratic formula, but i generally dont know where to start with this so any help would be much appreciated.

    "In an engineering test, a rocket sled is propelled into a target. The sledís distance d in meters from the target is given by the formula d = -1.5t^2 + 120 where t is the number of seconds after rocket ignition. How many seconds have passed since rocket ignition when the sled is 10 meters from the target?"
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor
    skeeter's Avatar
    Jun 2008
    North Texas
    you are given d = 10 ...

    10 = -1.5t^2 + 120

    1.5t^2 = 110

    t^2 = \frac{220}{3}

    since t > 0 ...

    t = \sqrt{\frac{220}{3}}
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 17
    Last Post: Oct 15th 2011, 09:34 PM
  2. Integration by parts (long question)
    Posted in the Calculus Forum
    Replies: 1
    Last Post: Jun 26th 2011, 10:02 AM
  3. how long is this cable? arc length question
    Posted in the Calculus Forum
    Replies: 2
    Last Post: Nov 12th 2009, 05:38 PM
  4. open ended pipe long question.
    Posted in the Geometry Forum
    Replies: 9
    Last Post: Jul 10th 2008, 10:36 AM
  5. one long question about coriolis force
    Posted in the Advanced Applied Math Forum
    Replies: 0
    Last Post: Mar 7th 2008, 09:56 PM

Search Tags

/mathhelpforum @mathhelpforum