SOLUTION: Throwing a wrench. An angry construction worker throws his wrench downward from a height of 128 feet with an initial velocity of 32 feet per second. The height of the wrench abo

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Question 327862: Throwing a wrench. An angry construction worker throws
his wrench downward from a height of 128 feet with an
initial velocity of 32 feet per second. The height of the
wrench above the ground after t seconds is given by
S(t)=-16t^2-32t+128
Found 2 solutions by Alan3354, josmiceli:
Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
I think you're right.

Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
S%28t%29=-16t%5E2-32t%2B128
When the wrench hits the ground, S%28t%29+=+0
since the height is zero.
0+=-16t%5E2-32t%2B128
The minus in front of the squared term tells
me the parabola solution has a maximum peak
Divide both sides by 16
-t%5E2+-+2t+%2B+8+=+0
t%5E2+%2B+2t+-+8+=+0
Complete the square
t%5E2+%2B+2t+%2B+%28-2%2F2%29%5E2+=+8++%2B+%28-2%2F2%29%5E2
+%28t+%2B+1%29%5E2+=+8+%2B+1
t+%2B+1+=+3
t+=+2 sec
The wrench will hit the ground in 2 seconds