SOLUTION: . If a stone is tossed from the top of a 350 meter building, the height of the stone as a function of time is given by h(t) = -9.8t2 – 10t + 350, where t is in seconds, and height

Algebra ->  Polynomials-and-rational-expressions -> SOLUTION: . If a stone is tossed from the top of a 350 meter building, the height of the stone as a function of time is given by h(t) = -9.8t2 – 10t + 350, where t is in seconds, and height       Log On


   

Question 387724: . If a stone is tossed from the top of a 350 meter building, the height of the stone as a function of time is given by h(t) = -9.8t2 – 10t + 350, 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 Earlsdon(6294) About Me  (Show Source):
You can put this solution on YOUR website!
Think about the height (h) of the stone when it reaches the ground!
It's zero! So you want to find the value of t (time) when the height (h) = 0.
h%28t%29+=+-9.8t%5E2-10t%2B350 Set h(t) = 0 and solve for t.
-9.8t%5E2-10t%2B350+=+0 Solve using the quadratic formula: t+=+%28-b%2B-sqrt%28b%5E2-4ac%29%29%2F2 and, here, a = -9.8, b = -10, and c = 350
When you do this you will get:
t+=+-6.50808 or t+=+5.4876 Discard the negative solution as the time, t, should be a positive quantity.
The stone will hit the ground after 5.49 seconds.