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Question 585157:  A bullet is shot vertically upward to a velocity of 96 ft/sec. The height h is in feet, atter t seconds is expressed by h=96t -16t^2. At what times was the bullet on the ground? At what time did the bullet reach its max height? What was the max height? 
 Answer by lwsshak3(11628)      (Show Source): 
You can  put this solution on YOUR website! A bullet is shot vertically upward to a velocity of 96 ft/sec. The height h is in feet, atter t seconds is expressed by h=96t -16t^2. At what times was the bullet on the ground? At what time did the bullet reach its max height? What was the max height? 
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h=96t -16t^2 
solving for t when bullet on the ground. 
h=0 
0=96t -16t^2 
complete the square 
-16t(t-6)=0 
t=0 (reject, t>0) 
t-6=0 
t=6 seconds 
.. 
h=96t -16t^2 
complete the square 
h=-16(t^2-6t+9)+144 
h=-16(t-3)^2+144 
This equation is that of a parabola that opens downwards with vertex at (3,144) 
.. 
ans: 
Bullet hit the ground in 6 sec 
Bullet reaches maximum height in 3 sec 
Maximum height=144 feet 
 
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