Results 1 to 2 of 2

Math Help - long question, help needed!

  1. #1
    Member
    Joined
    Nov 2008
    Posts
    85

    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
    Joined
    Jun 2008
    From
    North Texas
    Posts
    11,928
    Thanks
    757
    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: October 15th 2011, 09:34 PM
  2. Integration by parts (long question)
    Posted in the Calculus Forum
    Replies: 1
    Last Post: June 26th 2011, 10:02 AM
  3. how long is this cable? arc length question
    Posted in the Calculus Forum
    Replies: 2
    Last Post: November 12th 2009, 05:38 PM
  4. open ended pipe long question.
    Posted in the Geometry Forum
    Replies: 9
    Last Post: July 10th 2008, 10:36 AM
  5. one long question about coriolis force
    Posted in the Advanced Applied Math Forum
    Replies: 0
    Last Post: March 7th 2008, 09:56 PM

Search Tags


/mathhelpforum @mathhelpforum