OpenStudy (anonymous):

5 years ago
OpenStudy (anonymous):

?

5 years ago
OpenStudy (anonymous):

with what?

5 years ago
OpenStudy (anonymous):

An Li projected a ball into the air at 32 feet per second from a platform 48 feet off the ground. The path of the ball is represented by the equation s(t) = -16tsquared + 32t + 48, where s is the height of the ball and t is the time, in seconds, after the ball was projected. How many seconds will it take the ball to reach the ground?

5 years ago
OpenStudy (anonymous):

Answer choices: a - 1 b - 2 c - 3 d- 4 Please explain. ;3

5 years ago
OpenStudy (anonymous):

set s(t) = 0

5 years ago
OpenStudy (anonymous):

when ball is on the ground, height is 0.

5 years ago
OpenStudy (anonymous):

try plugging in the answer in the variable and see if it matches up

5 years ago
OpenStudy (anonymous):

^ or do that.

5 years ago
OpenStudy (anonymous):

hahah it works ya know!

5 years ago
OpenStudy (anonymous):

Oh s(t) = 0?

5 years ago
OpenStudy (anonymous):

which one of those answers makes 0

5 years ago
OpenStudy (anonymous):

For the t_squared do we actually have to square it

5 years ago
OpenStudy (anonymous):

Im still confused...Im bad at math :/

5 years ago
OpenStudy (anonymous):

same here but i try even though what your doing is beyond my level

5 years ago
OpenStudy (anonymous):

After you set it to zero, what method are you pose to use?

5 years ago
OpenStudy (anonymous):

like i said try plugging in the answer into the T and see what you get if which one will equal the zero=s(t)

5 years ago
OpenStudy (anonymous):

Is 0 pose to = 0 when you get the right answer o-o

5 years ago
OpenStudy (anonymous):

ok i got it the answer should be t=3

5 years ago
OpenStudy (anonymous):

well, you're finding t, so s(t) = 0, find t.

5 years ago
OpenStudy (anonymous):

Okie I get it just keep plugging Q~Q So much work. Ty.

5 years ago
OpenStudy (anonymous):

no, don't just keep plugging in, it won't work in the future if it's not multiple choice.

5 years ago
OpenStudy (anonymous):

Oh its for getting ready for cst

5 years ago
OpenStudy (anonymous):

it's a waste of time on a test also.

5 years ago
OpenStudy (anonymous):

only plugg in to find answer but eventualy youll need to work it out to get the answer you got

5 years ago
OpenStudy (anonymous):

I dont gte how to find it by setting it to 0 tho

5 years ago
OpenStudy (anonymous):

set it to 0, then isolate for t. what do you not get.

5 years ago
OpenStudy (anonymous):

take your equation for the path of the ball, notice how everything in the equation is a mulitple of 16? we can take out that sixteen and get rid of it because we only want to know when your equation =0 your new equation: (-x^2 +2x +3)=0 we can factor this into (-x+3)(x+1)=0 the equation will be zero when either of these = 0 from this we can have 2 answers: one at x=-1 one at x=3 since time can't go backwards, the only answer we have left is at x=3

5 years ago
OpenStudy (anonymous):

isnt there more than one t tho? so how do you isolate. o-o

5 years ago
OpenStudy (anonymous):

yes, there is more than one t. if you look at my solution you will see that i have 2 "x"s that work, but one of them is negative, so we can't use it as a solution, because the ball can't go back in time

5 years ago
OpenStudy (anonymous):

OMG. I cant believe I fogot that. Lol. My teacher taught me that three days ago...

5 years ago
OpenStudy (anonymous):

Ty.

5 years ago
OpenStudy (anonymous):

Np. Better than studying Calculus 4 like i should be

5 years ago
OpenStudy (anonymous):

Im not in that grade tho. Lol.

5 years ago
OpenStudy (anonymous):