SOLUTION: An object is propelled upward from 12 meters above ground with an initial velocity of 120 meters/second. It's height can be modeled by the equation s(t)=-5t^2 +120t+12 meters, whe

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Question 1188917: An object is propelled upward from 12 meters above ground with an initial velocity of 120 meters/second.
It's height can be modeled by the equation s(t)=-5t^2 +120t+12 meters, where t is time in seconds.
It's velocity can be modeled by the equation v(t)=-10t+120 meters/second, where t is time in seconds.
At what velocity did the object hit the ground?

Found 2 solutions by ikleyn, Alan3354:
Answer by ikleyn(52794) About Me  (Show Source):
You can put this solution on YOUR website!
.


            This problem is to be solved in two steps.


(1)  First step is to solve this quadratic equation

         -5t^2 + 120t + 12 = 0


     to determine the time when the object will hit the ground.



(2)  The second step is to substitute the found value of "t" into the formula for the velocity the object will hit the ground.


This value will be negative, which means that the velocity is directed vertically down.

Happy calculations (!)




Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
An object is propelled upward from 12 meters above ground with an initial velocity of 120 meters/second.
It's [sic] height can be modeled by the equation s(t)=-5t^2 +120t+12 meters, where t is time in seconds.
It's [sic] velocity can be modeled by the equation v(t)=-10t+120 meters/second, where t is time in seconds.
At what velocity did the object hit the ground?
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Find t when s(t) = 0
s(t)=-5t^2 +120t+12 = 0
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Then solve for v(t).
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PS it's = it is