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Homework Help: Stuck on algebra again

  1. Oct 3, 2006 #1
    hey hey.. I need help again. I can't belive i've forgotten my simple algebra. Anyway.. is there a way to solve the following without using the quadratic equation?

    0 = (22)t + 1/2(-9.8)t^2

    I'm tryin to isolate t, so i can solve for time. I know you can factor it out as follows..

    0 = [22 + 1/2(-9.8)t]t

    Thats where I am stuck... how do i get this in the form.. t = xxxxx

    Thanks for the help..
     
  2. jcsd
  3. Oct 3, 2006 #2
    [tex] 22t -4.9t^{2} = 0 \rightarrow t(22-4.9t) = 0 [/tex]

    [tex] t = 0 [/tex] or [tex] 22-4.9t = 0, t = 4.49 [/tex]
     
  4. Oct 3, 2006 #3
    where did the 4.9 come from? nevermind.. figured that out.. THANKS!>. i feel really dumb now because i shoulda known that.. sometimes i complicate myself too much.
     
    Last edited: Oct 3, 2006
  5. Oct 3, 2006 #4
    Thats usually the best method but for this one it is not necessary.
    Picking up from u
    0 = [22 + 1/2(-9.8)t]t
    Therefore
    t = 0 and 22 + 1/2 (-9.8)t =0
    finally:
    t= 0, 4.49s

    I think it is the second answer that you probably want. Since this type of question is probably asking when the onject will return to its original position.
     
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