SOLUTION: If a stone is tossed from the top of a 270 meter building, the height of the stone as a function of time is given by h(t) = -9.8t2 � 10t + 270, where t is in seconds, and height is

Question 624960: If a stone is tossed from the top of a 270 meter building, the height of the stone as a function of time is given by h(t) = -9.8t2 � 10t + 270, 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 Alan3354(69443) (Show Source): You can put this solution on YOUR website!
h(t) = -9.8t2 � 10t + 270
It hits the ground then h = 0
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h(t) = -9.8t2 � 10t + 270 = 0

Solved by pluggable solver: SOLVE quadratic equation (work shown, graph etc)

Quadratic equation (in our case ) has the following solutons:

For these solutions to exist, the discriminant should not be a negative number.

First, we need to compute the discriminant : .

Discriminant d=10684 is greater than zero. That means that there are two solutions: .

Quadratic expression can be factored:

Again, the answer is: -5.78384879976431, 4.763440636499. Here's your graph:

==============
t = x
Ignore the negative solution.
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t = 4.76 seconds
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Gravitional acceleration on Earth =~ 9.8 meters/sec/sec
The equation for the vertical position should be:
h(t) = -4.9t^2 � 10t + 270
not -9.8t^2
==============
It might be -9.8t^2 on some other planet somewhere, but not here.

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