Answer:
- A) 9 ft
- B) 13 ft
- C) 1/2 second
Explanation:
Your notes on the problem tell you how to work it.
Part A. The height of the ball when t=0 is d(0) = 9 . . . . feet.
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Part C. (Your notes rightly say work this first.)
... t = -b/(2a) = -16/(2(-16)) = 1/2
The ball reaches its maximum height after 1/2 second.
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Part B. d(1/2) = 16t(-t+1) +9 = (16)(1/2)(-1/2 +1) +9 = 4 +9 = 13 . . . . feet.
The maximum height is 13 ft.