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Math Help - College Algebra Urgent Help!!

  1. #1
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    College Algebra Urgent Help!!

    Hey everyone. I need some major help. Here is my question.

    The height of a ball thrown up at 320 feet per second is given by:
    h(t)=-16tsquared +320t+5. Find the maximum height the ball reaches. Please help!

    Thanks
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  2. #2
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    Good luck.

    -Andy
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  3. #3
    A riddle wrapped in an enigma
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    Quote Originally Posted by bulldogben21 View Post
    Hey everyone. I need some major help. Here is my question.

    The height of a ball thrown up at 320 feet per second is given by:
    h(t)=-16tsquared +320t+5. Find the maximum height the ball reaches. Please help!

    Thanks
    Abender: I'm a little slow today trying to make it look pretty.

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  4. #4
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    Man thank you so much. You have no idea how much that helped
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  5. #5
    Super Member Matt Westwood's Avatar
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    The ball goes up, reaches its maximum height, stops, then starts coming down again.

    The operative word there is "stops".

    So if you can find the value of h when t is equal to zero you're made.

    From the equations of motion you've got

    h = u t + 1/2 a t^2

    where u = 320, a = -32 and h is the value you're trying to find. This matches the equation you've been given, except for the 5. So write it:

    h - 5 = -16 t^2 + 320 t

    The 5 signifies the extra 5 feet above the ground you start throwing the ball upwards from.

    So now you can look at the equation of motion that goes:

    v^2 = u^2 + 2 a (h-5)

    You've got v, it's equal to zero (see above), and h is what you want to find.

    So you have h-5 = (v^2 - u^2) / (2 a)

    and plugging in the numbers you get

    h-5 = (0 - 320^2) / (2 x (-32))

    that should be enough, you should be able to work it out from there.
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  6. #6
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    Oooops, my apologies for introducing calculus on a thread titled "College Algebra Urgent Help!!" Thank you for catching this masters.
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