9514 1404 393
Answer:
- t = 0.697 seconds
- never (the maximum height is 100 ft)
Step-by-step explanation:
A graphing calculator provides a nice solution to this question.
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1) Put 48 ft in for H and solve for t:
48 = -16t^2 +80t
-3 = t^2 -5t
3.25 = t^2 -5t +6.25 = (t -2.5)^2
t = 2.5 ±√3.25
The ball will first reach 48 feet at t = 2.5 -√3.25 ≈ 0.697224 seconds.
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2) The equation tells us the maximum height occurs at t=2.5 seconds. That height is ...
H = -16(2.5^2) +80(2.5) = 100
The maximum height is 100 feet. The ball will never reach 110 feet.
