Algebra

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An object is launched upward from the ground with an initial vertical velocity of 40 feet per second. After how many seconds does the object reach a height of 25 feet? I need to use the vertical motion model. Here is my work so far.
h = -17t^2 + 40t + 25

  • Algebra -

    I meant -16t^2

  • Algebra -

    your opening function should be
    h = -16t^2 + 40t
    h is supposed to have a value of 25
    25 = -16t^2 + 40t
    16t^2 - 40t + 25 = 0 , looks like a perfect square
    (4t - 5)^2 = 0
    4t = 5
    t = 5/4

    it will take 5/4 seconds

    I don't know what "vertical motion model" means, never heard that term

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