SOLUTION: Can someone please help me? If a stone is tossed from the top of a 230 meter building, the height of the stone as a function of time is given by h(t) = -9.8t2 – 10t + 230, whe

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Question 494578: Can someone please help me?

If a stone is tossed from the top of a 230 meter building, the height of the stone as a function of time is given by h(t) = -9.8t2 – 10t + 230, 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 ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
If a stone is tossed from the top of a 230 meter building, the height of the stone as a function of time is given by h(t) = -9.8t2 – 10t + 230, 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.
:
When the stone hits the ground the height is zero, hence h(t) = 0, so write the equation:
-9.8t^2 - 10t + 230 = 0
You have to use the quadratic formula to solve this problem
x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+
In this problem: x=t; a=-9.8; b=-10; c=230
:
t+=+%28-%28-10%29+%2B-+sqrt%28-10%5E2-4%2A-9.8%2A230+%29%29%2F%282%2A-9.8%29+
:
t+=+%2810+%2B-+sqrt%28100+%2B+9016+%29%29%2F%28-19.6%29+
I'll let you do the rest of the math here, the positive solution is the no. of seconds for the stone to hit the ground