SOLUTION: a student dropped his cell phone from a floor with a height of 81 feet. the heigh of the phone after t seconds is given by the quadradic equation h=-9t^2+81. how long will it take
Question 402749: a student dropped his cell phone from a floor with a height of 81 feet. the heigh of the phone after t seconds is given by the quadradic equation h=-9t^2+81. how long will it take for the cell phone to hit the ground? Answer by nerdybill(7384) (Show Source):
You can put this solution on YOUR website! a student dropped his cell phone from a floor with a height of 81 feet. the heigh of the phone after t seconds is given by the quadradic equation h=-9t^2+81. how long will it take for the cell phone to hit the ground?
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Set h to 0 and solve for t:
h=-9t^2+81
0=-9t^2+81
-81=-9t^2
9 = t^2
3 seconds = t
