SOLUTION: A catapult is designed to launch extreme circus performers to ridiculous heights from a raised platform. After launch, the height of the performer in feet is given by h(t)=-16t^2+8

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Question 1098710: A catapult is designed to launch extreme circus performers to ridiculous heights from a raised platform. After launch, the height of the performer in feet is given by h(t)=-16t^2+80t+32. Where t is seconds after the launch. After how many seconds is the performer 100 feet above the ground?
Answer by Boreal(15235) About Me  (Show Source):
You can put this solution on YOUR website!
h(t)=-16t^2+80t+32=100
-16t^2+80t-68
=-4t^2+20t-17 or 4t^2-20t+17=0
t=(1/8)(20+/-sqrt(400-272)); sqrt 128=11.3
t=(1/8)(20+/-11.3)
t=31.3/8 or 3.91 sec;
t=8.7/8 or 1.09 sec
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