Question

A punter kicks a football upward with an initial speed of 48 feet per second. After how many seconds does the ball hit the ground? Use the formula h = rt - 16t2 where h represents height in feet and r represents the initial speed.

Answer 1

@sleepyhead314

Answer 2

they gave you r = 48
so you now have h = 48t - 16t^2
ground level would be a height of 0 so h = 0

so solve for 0 = 48t - 16t^2

Answer 3

hint: factor out the (-16t)

Answer 4

i facctored out 16 and got 0=16(3-t^2) but i dont think this is even an answer?

Answer 5

did ya see my hint? :P
it would help to take out one of the " t "s too

Answer 6

0=-16t(-3+t)
or
0=16t(3-t)
?

Answer 7

i dont know what to do after this though?

Answer 8

either or would do fine :)
you should be able to get the answer out of them anyways

well, for example how would you solve something like (x+1)(x-3) = 0 ?
it would be kind of the same idea :)

Answer 9

it has to be a numerical answer...

Answer 10

I know, you'll get a numerical number
do you know how to get an answer out of something like (x+2)(x-3)= 0?

Answer 11

x=-2 and x=3. so the answer is 3 because theres no such thing as -2 seconds lol

Answer 12

mmmmmmmmmmm
that was just an example
(16t)(3-t)=0 same idea

Answer 13

t=0 and t=3 ?

Answer 14

yes :)
so the ball leaves the ground at time 0
and hits back on the ground at time 3

Answer 15

Thank you!!!

Answer 16

you're welcome :)

Answer 17

i know its late but i have just one more and i promise i'll let you go to bed...? >.<

Answer 18

yeah yeah >,< one more, quickly though :P

Answer 19

actually i went ahead and did it! okay goodnight now!! THANK YOU SOSOSOSO MUCH FOR EVEYTHING!!!!

Answer 20

lol I'm glad I could help ^_^ good night <3