Answer:
Option B. 1.8 seconds
Step-by-step explanation:
h=-16t^2+56t+1
This is a quadratic equation, and its graph is a parabola
h=at^2+bt+c; a=-16, b=56, c=1
Like a=-16<0 the parabola opens downward, and it has a maximum value (height) at the vertex, at the abscissa:
Replacing the known values:
Approximately 1.8 seconds.
Answer: It takes approximately 1.8 seconds the airplane to reach its maximum height.
