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Thread: Ball At Max Height

  1. November 17th 2008, 10:23 PM #1
    magentarita
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    Ball At Max Height

    Vanessa throws a tennis ball in the air.
    The function h(
    t) = –16t^2 + 45t + 7 represents the distance, in feet, that the ball is from the ground at any
    time     t. At what time, to the nearest tenth of a second, is the ball at its maximum height?
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  2. November 18th 2008, 11:24 AM #2
    Soroban
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    Hello, magentarita!


    Vanessa throws a tennis ball in the air.
    The function h(t) \:=\:–16 t^2+ 45t+ 7 represents the distance, in feet,
    that the ball is from the ground at any time t.
    At what time, to the nearest tenth of a second, is the ball at its maximum height?
    The graph is a down-opening parabola. .Its maximum is at its vertex.

    The vertex is: . t \:=\:\frac{\text{-}b}{2a} \:=\:\frac{\text{-}45}{2(\text{-}16)} \:=\:\frac{45}{32}\:=\:1.40625

    The ball is at maximum height in about 1.4 seconds.
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  3. November 18th 2008, 09:35 PM #3
    magentarita
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    great work...........

    Quote Originally Posted by Soroban View Post
    Hello, magentarita!


    The graph is a down-opening parabola. .Its maximum is at its vertex.

    The vertex is: . t \:=\:\frac{\text{-}b}{2a} \:=\:\frac{\text{-}45}{2(\text{-}16)} \:=\:\frac{45}{32}\:=\:1.40625

    The ball is at maximum height in about 1.4 seconds.
    I hope that you can help me with questions privately.
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