SOLUTION: The equationh=-16t^2+112t gives the height of an arrow, shot upward from the ground with an initial velocity of 112 ft/s, where t is the time after the arrow leaves the ground. F

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Question 75192: The equationh=-16t^2+112t gives the height of an arrow, shot upward from the ground with an initial velocity of 112 ft/s, where t is the time after the arrow leaves the ground. Find the time it takes for the arrow to reach a height of 180 ft.
please show your work
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
h(t)=-16t^2+112t
Let the height be 180 ft. then:
-16t^2+112t-180=0
4(-4t^2+28t-45)=0
Use the Quadratic Formula to find "t".
t=[-28+-sqrt(784-4*-4*-45)]/-8
t=[-28+-8]/-8
t=-36/-8=4.5 seconds
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Cheers,
Stan H.