SOLUTION: 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 i

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Question 671667: 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 mananth(16946) About Me  (Show Source):
You can put this solution on YOUR website!
h(t) = -9.8t^2 – 10t + 230,
When the stone hits the ground h(t)=0
-9.8t^2 – 10t + 230 = 0
This is a quadratic equation. Use the formula method.
here a=-9.8, b=-10, c=230
a= -9 4/5 b= -10 c= 230

b^2-4ac= 100 - -9016
b^2-4ac= 9116 sqrt%28%099116%09%29= 95.48
x=%28-b%2B-sqrt%28b%5E2-4ac%29%29%2F%282a%29
x1=%28-b%2Bsqrt%28b%5E2-4ac%29%29%2F%282a%29
x1=( 10 + 95.48 )/ -19.6
x1= -5.38
x2=( 10 - 95.48 )/ -19.6
x2= 4.36 seconds
Ignore negative value
x = -5.38 mph


m.ananth@hotmail.ca