Question 1025197: The Skywalk is a glass-bottomed platform that hangs over the edge of the Grand Canyon and is suspended 4000 feet above the floor of the canyon. If a tourist shot an arrow straight up in the air from the observation platform, the arrow's height could be modeled by
H(t) = −16t2 + 240t + 4000
where H(t) is the height of the arrow above the canyon floor in feet t seconds after being shot.
(a) Find H(3) and explain its meaning. (Include units with your numerical answers.)
After, the arrow was at a height of_____.
(b) Use factoring to determine how many seconds before the arrow was at a height of 1536 feet. (Include units with your numerical answer.)
It took about______for the arrow to get to 1536 feet.
(c) Use factoring to determine after how many seconds the arrow would hit the canyon floor. (Include units with your numerical answer.)
After, _____ the arrow hits the canyon floor.
Answer by KMST(5328)   (Show Source):
You can put this solution on YOUR website!  defined for the time that the arrow is in flight,
 and  such that  ,
is the height of the arrow above the canyon floor in feet seconds after being shot.
(a) 
After  seconds, the arrow was at a height of  feet.
(b)
 .
Dividing both sides of the equal sign by  we get the equivalent equation
 , which we can solve by factoring:
--> --> --> .
 does not make sense; it is not in the domain of the function, where it must be ,
so the answer is  .
It took about  seconds))) for the arrow to get to 1536 feet.
c) When the arrow hits the canyon floor, it is  feet above the canyon floor, so
 , which means 
Dividing both sides of the equal sign by we get the equivalent equation
 , which we can solve by factoring:
--> --> --> .
 does not make sense; it is not in the domain of the function, where it must be ,
so the answer is  .
After  seconds, the arrow hits the canyon floor.
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