SOLUTION: The height h in feet of an object after t seconds is given by the function h=-16t^2+30t+7. How long will it take the object to hit the ground? Round your answer to the nearest thou

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Question 118353: The height h in feet of an object after t seconds is given by the function h=-16t^2+30t+7. How long will it take the object to hit the ground? Round your answer to the nearest thousandth.
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
The height h in feet of an object after t seconds is given by the function h=-16t^2+30t+7. How long will it take the object to hit the ground? Round your answer to the nearest thousandth.
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When it hits the ground the height is zero.
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h(t) =-16t^2+30t+7
Let h(t)=0 and solve for "t":
-16t^2+30t+7 = 0
t = [-30 +- sqrt(30^2-4*-16*7)]/-32
t = [-30 +- sqrt(1348)]]/-32
t = [-30 +- 36.7151]/-32
Positive answer:
t = [-30-36.715]/-32
t = 2.0848 seconds
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Cheers,
Stan H.