If an object is dropped from a height of 126 feet, the function h(t) = –16t2 + 126 gives the height of the object after t seconds. Approximately when will the object hit the ground? Round to the nearest hundredth.

I know the answer is 2.81 but, how do I do the work to find the problem that gives me that answer???

Question

If an object is dropped from a height of 126 feet, the function h(t) = –16t2 + 126 gives the height of the object after t seconds. Approximately when will the object hit the ground? Round to the nearest hundredth.

I know the answer is 2.81 but, how do I do the work to find the problem that gives me that answer???

vocaloid · Answer

set the equation equal to 0 (since h = 0 when it's on the ground)

vocaloid · Answer

0 = –16t2 + 126 

know where to go from there?

anime_lover_levi · Answer

So turn the T into a 0?
(Btw gakupo , kaito and len/rin are my fav XD)

vocaloid · Answer

no, you're solving FOR t

vocaloid · Answer

start by subtracting 126 from each side

anime_lover_levi · Answer

ok

vocaloid · Answer

-126 = -16t^2

vocaloid · Answer

divide both sides by 16

vocaloid · Answer

7.875 = t^2

vocaloid · Answer

then solve for t

anime_lover_levi · Answer

then.....hmm... sorry I'm bad at math so I'm trying to prossess

vocaloid · Answer

to solve

7.875 = t^2

take the square root of both sides

vocaloid · Answer

sqrt(7.875) = 2.81 which matches your answer

vocaloid · Answer

let me know if you need me to explain a certain step

anime_lover_levi · Answer

i will I'm just reading back and making sure ig to it, math is like y worst subject

vocaloid · Answer

ok, great!

anime_lover_levi · Answer

so you square 7.875?

vocaloid · Answer

take the square root

vocaloid · Answer

sqrt(7.875) which is the opposite of squaring

anime_lover_levi · Answer

ok I think I understand :)