Question 184005
S(t)= -16t^2-32t+128 
A)What is the height of the wrench after 1 second?
s(1) = -16-32+128 = 80 ft
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B)How long does it take for the wrench to reach the ground?
Height is zero when the wrench is on the ground.
-16t^2-32t+128 = 0

Divide thru by -16 to get:

t^2 + 2t - 8 = 0

Factor:

(t+4)(t-2) = 0
Positive solution:
t = 2 seconds
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Cheers,
Stan H.