SOLUTION: If a stone is tossed from the top of a 210 meter building, the height of the stone as a function of time is given by h(t) = -9.8t2 – 10t + 210, where t is in seconds, and height i

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons  -> Quadratic Equation Lesson -> SOLUTION: If a stone is tossed from the top of a 210 meter building, the height of the stone as a function of time is given by h(t) = -9.8t2 – 10t + 210, where t is in seconds, and height i      Log On


   

Question 410250: If a stone is tossed from the top of a 210 meter building, the height of the stone as a function of time is given by h(t) = -9.8t2 – 10t + 210, where t is in seconds, and height is in meters. After how many seconds will the stone hit the ground? Round to the nearest hundredth’s place; include units in your answer
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!


Hi

h(t) = -9.8t^2 – 10t + 210, where t is in seconds, and height is in meters

when it hits the ground: h(t) = 0

 -9.8t^2 – 10t + 210 = 0   |multiplying thru by -10

  98t + 100t - 2100 = 0

  49t^2 + 50t - 1050 = 0

t+=+%28-50+%2B-+sqrt%28+208300%29%29%2F%2898%29+  |tossing out negative solution for time

  t = 4.15  (rounded to the nearest hundredth's place)