Question

Quadratics word problem

Answer 1

An arrow is shot upward from a platform 40 feet high with an initial velocity of 224 ft. per second. its height, h, in feet after t seconds is given by the equation: h= -16t^2 + 224t+40. At what times will the arrow be 824 feet above the ground?

Answer 2

Am i supposed to plug in 824 for t?

Answer 3

no, \(t\) is the time you are looking for
you are supposed to replace \(h\) by 824 and solve for \(t\)

Answer 4

h is replaced by 824

Answer 5

\[
\begin{array}{rcl}
h(t) &=& -16t^2 + 224t+40 \\
824 &=& -16t^2 + 224t+40 \\
0 &=& -16t^2 + 224t+40-824
\end{array}
\]
Quadratic formula.

Answer 6

Ohh ok i see it now.. then you just factor, correct?

Answer 7

Ummm, you're solving for \(t\) here. You can factor or use quadratic formula or whatever method you want.

Answer 8

I see.. thanks!