SOLUTION: The height h in feet of an object after t seconds is given by the function h = - 16t2 + 80t + 6. How long will it take the object to hit the ground? Round y

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons  -> Quadratic Equation Lesson -> SOLUTION: The height h in feet of an object after t seconds is given by the function h = - 16t2 + 80t + 6. How long will it take the object to hit the ground? Round y      Log On


   

Question 1158980: The height h in feet of an object after t seconds is given by the function
h = - 16t2 + 80t + 6.
How long will it take the object to hit the ground? Round your answer to the nearest thousandth.
Answer by ikleyn(52778) About Me  (Show Source):
You can put this solution on YOUR website!
.

For it, you need to solve this quadratic equation


    -16*t^2 + 80t + 6 = 0.

Or

    16*t^2 - 80t - 6 = 0


    t%5B1%2C2%5D = %2880+%2B-+sqrt%2880%5E2+-+4%2A16%2A%28-6%29%29%29%2F%282%2A16%29 = %2880+%2B-+82.365%29%2F32.


You do not need negative root - it makes no sense.


You need only positive root  t =  %2880+%2B+82.365%29%2F32 = 5.074.   (rounded)


ANSWER.  5.074 seconds.

Solved.