SOLUTION: If a stone is tossed from the top of a 190 meter building, the height of the stone as a function of time is given by h(t) = -9.8t^2 -10t +190, where t is in seconds, and height is

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Question 549675: If a stone is tossed from the top of a 190 meter building, the height of the stone as a function of time is given by h(t) = -9.8t^2 -10t +190, 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 josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
+h%28t%29+=+-9.8t%5E2+-10t+%2B190+
Note that if I make +t+=+0+, which is
when the stone is thrown from the
top of the building, I get +190+ ft as I should:
+h%280%29+=+-9.8%2A0%5E2+-10%2A0+%2B190+
+h%280%29+=+190+
The problem wants to know what is t
when +h%28t%29+=+0+, or ground level.
+0+=+-9.8t%5E2+-10t+%2B190+
Use the quadratic formula
t+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+
+a+=+-9.8+
+b+=+-10+
+c+=+190+

t+=+%28+10+%2B-+sqrt%28+100+%2B+4%2A%28-9.8%29%2A190+%29%29%2F%28-19.6%29%29+
t+=+%28+10+%2B-+sqrt%28+100+%2B+4%2A%28-9.8%29%2A190+%29%29%2F%28-19.6%29%29+
I can't finish this because my cat, the Widster, just curled
up beside me, and I'm not going to disturb him to get a calculator.
But you get the idea.