Answer:
20 seconds
Step-by-step explanation:
We just need the x-coordinate of the vertex...so find -b/(2a) and we are done:
-b/(2a)=-640/(2*-16)=-640/-32=20
20 second
Answer:
[tex]\boxed{\text{20 s}}[/tex]
Step-by-step explanation:
The standard form of a quadratic function is
y = ax² + bx + c
Your function is
h(t) = -16t²+ 640t
a = -16; b = 640; c = 0
a is negative, so you have a downward-opening parabola.
The vertex form of a parabola is
y = a(x - h)² + k
where (h, k) is the vertex of the parabola.
h = -b/(2a) and k = f(h)
Your parabola opens downward, so the vertex is a maximum.
Calculate h
[tex]h = \dfrac{640}{-2(-16)}} = \dfrac{640}{32} = 20\\\text{The projectile reaches maximum height }\boxed{\textbf{20 s}} \text{after it is thrown}\\[/tex]
The figure below shows the graph of h(t).
