If a stone is tossed from the top of a 330 meter building, the height of the stone as a function of time is given by h(t) = -9.8t2 – 10t + 330, 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. Show the work. I have tried the quadratic formula, factoring, and completing the square, but no such luck...Please help me!!

Question

anonymous · Answer

It does not factor. Hold on. Let's try the quad formula.

anonymous · Answer

Or use the calculator. I get x = 5.32 secs. Is that right?

anonymous · Answer

Use quad formula. You get x = 10 +/- sqrt(100-4(-9.8)(330)) all over -19.6

anonymous · Answer

That simplifies to 10 +/- sqrt(13036) over -19.6

anonymous · Answer

I didn't get that answer using the quad formula
\[-b +-\sqrt{(b)^2 - 4ac} / 2a

anonymous · Answer

Ignore the negative answer. You get (10-114.1753)/-19.6 = 5.315066521 or about 5.32 to the nearest hundredth. How's that look?

anonymous · Answer

oh I can really ignore the negative answer?!

anonymous · Answer

Yes, because time can't be negative

anonymous · Answer

right thanks so much!!

anonymous · Answer

The domain in this problem is x greater than or equal to 0

anonymous · Answer

You're welcome. How 'bout a medal?