Question

If a baseball player hits a baseball from 4 feet off the ground with an initial velocity of 64 feet per second, how long will it take the baseball to hit the ground? Use the equation h = -16t2 + 64t + 4. ?

Answer 1

@esamalaa

Answer 2

h = -16t2 + 64t + 4. <--- notice is a parabola, leading coefficient is negative, thus so set y = 0 and solve for "x" \(\bf 0 = -16t^2 + 64t + 4\)

Answer 3

"t" rather =)

Answer 4

that's the prob.. I need help.

Answer 5

\(\bf h= -16t^2 + 64t + 4\implies 0= -16t^2 + 64t + 4\\ \quad \\
\implies 0= -4(4t^2 - 16t - 1)\implies 0=(4t^2 - 16t - 1)\)

so there, just factor it out

Answer 6

is it 2(plus or minus) sqrt17/2?

Answer 7

hmm dunno what factors did you get?

Answer 8

I'd think you'd need to use the quadratic formula for this one, it won't factor out to integers

Answer 9

\(\bf \qquad \qquad \qquad 0=({\color{blue}{ 4}}t^2 {\color{red}{ -16}} t {\color{green}{ -1}})\\
\textit{quadratic formula}\\
y={\color{blue}{ a}}x^2+{\color{red}{ b}}x+{\color{green}{ c}}
\qquad \qquad
x= \cfrac{ - {\color{red}{ b}} \pm \sqrt { {\color{red}{ b}}^2 -4{\color{blue}{ a}}{\color{green}{ c}}}}{2{\color{blue}{ a}}}\)