Question

This is super hard.. Can anyone help me please?Before a football game, a coin toss is used to determine which team will kick off. The height h (in feet) of a coin above the ground t seconds after being flipped up into the air is given by h= -16t^2 + 12t +4 . How long does a team captain have to call heads or tails if it must be done while the coin is in the air?

Answer 1

it's not that hard... without all those words, you'll end up having to solve this equation:
\[\large 0=-16t^2+12t+4 \]
can you solve that equation for t?

Answer 2

@dpaInc 4(4t^2 + 3t + 1) ?

Answer 3

you factored a 4 or -4?

Answer 4

whoops -4

Answer 5

let's factor out the -4

Answer 6

\[\large -4(4t^2-3t-1)=0 \]
\[\large 4t^2-3t-1=0 \]

Answer 7

Ok I got that so far

Answer 8

now you can either factor this (which is possible, btw) or if you don't want to think, just use the quadratic formula....

Answer 9

what do you wanna do?

Answer 10

I only know how to factor how would I use the formula though?

Answer 11

t=-1/4 t=1 ?

Answer 12

ok... before using the formula, the equation needs to be in standard from so you can identify the coefficients a, b, and c:

standard form: \(\large at^2+bt+c=0 \)
quadratic formula: \(\large t=\frac{-b\pm \sqrt{b^2-4ac}}{2a} \)

Answer 13

@dpaInc I got t= -1/4 t=1 So it's wanting to know... How long does a team captain have to call heads or tails if it must be done while the coin is in the air? And the answers are in seconds?...

Answer 14

in your equation,
a=4
b=-3
c=-1

plug these values into the formula for your answer... notice you'll get two values... choose the one that makes sense in the real world... choose the positive t...

Answer 15

yes... seconds....

Answer 16

so @dpaInc 1 second?

Answer 17

@dpaInc Is 1 sec correct?

Answer 18

yes...

Answer 19

Why wouldn't it be 0.25 sec? @dpalnc

Answer 20

Your other solution was t = -1/4, but that doesn't make sense in this context because you can't have a negative time.

Answer 21

So you ignore that solution

Answer 22

Oh ok I get it thanks so much!!!!! @jim_thompson5910

Answer 23

you're welcome