SOLUTION: The projected path of Donovan’s touchdown pass is represented by the following function: h = -t2 + 5t, where h represent the height of the ball after t seconds. How much time is th

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Question 926240: The projected path of Donovan’s touchdown pass is represented by the following function: h = -t2 + 5t, where h represent the height of the ball after t seconds. How much time is the ball in the air before it hits the ground?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
The ball is in the air until +h+=+0+, which
means it is back on the ground
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The ball is thrown at +t+=+0+, so can say:
+h%280%29+=+-0%5E2+%2B+5%2A0+
+h%280%29+=+0+
This is the instant the ball is thrown
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Then I let +h+=+0+ to find when it is back
on the ground
+0+=+-t%5E2+%2B+5t+
+0+=+t%2A%28+-t+%2B+5+%29+
+t+=+5+
The ball hits the ground in +5+ sec