SOLUTION: A ball is thrown vertically upward from the top of a cliff. The height of the ball is modeled by the function h(t) = 65 + 10t - 5t^2, where h(t) is the height in metres and t is th

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Question 669376: A ball is thrown vertically upward from the top of a cliff. The height of the ball is modeled by the function h(t) = 65 + 10t - 5t^2, where h(t) is the height in metres and t is the time in seconds. Determine when the ball reaches its maximum height.
Answer by nerdybill(7384) About Me  (Show Source):
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A ball is thrown vertically upward from the top of a cliff. The height of the ball is modeled by the function h(t) = 65 + 10t - 5t^2, where h(t) is the height in metres and t is the time in seconds. Determine when the ball reaches its maximum height.
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equation is
h(t) = 65 + 10t - 5t^2
h(t) = -5t^2 + 10t + 65
the max height is reached at the vertex.
the value of t at the vertex is:
t = -b/(2a)
t = -10/(2(-10))
t = -10/(-20)
t = 10/(20)
t = 1/2 seconds (answer)