Solve the problem.
-A model rocket is launched from a raised platform at a speed of 112 feet per second. Its height in feet is given by $h ( t ) = - 16 t ^ { 2 } + 112 t + 20$ t = seconds after launch). After how many seconds does
The object reach its maximum height?
A) 5.5 seconds
B) 20 seconds
C) 1.75 seconds
D) 3.5 seconds

Question

Quizplus · Accepted Answer

The maximum height of a projectile in a quadratic equation of the form $h(t) = at^2 + bt + c$ is found at $t = -\frac{b}{2a}$. Here, $a = -16$ and $b = 112$, so $t = -\frac{112}{2(-16)} = 3.5$ seconds.

Solve the Problem h(t)=−16t2+112t+20h ( t ) = - 16 t ^ { 2 } + 112 t + 20h(t)=−16t2+112t+20

Solve the Problem $h ( t ) = - 16 t ^ { 2 } + 112 t + 20$