Question

Pablo and max's follows a flight pattern approximatley modled by the equation h(t)=-8t^2+16t+2 where h(t)is their rocket's height in meters t seconds after launch. How many seconds was their rocket in the air

Answer 1

Answer: 2.11 s

Step-by-step explanation:

Given

Equation of rockets height is given by

$\Rightarrow h(t)=-8t^2+16+2$

Height will be zero once the rocket lands on the ground

So, we can write

$\Rightarrow h(t)=0\ \text{or}\ -8t^2+16t+2=0\\\Rightarrow 8t^2-16t-2=0\\\\\Rightarrow t=\dfrac{16\pm \sqrt{(-16)^2-4(8)(-2)}}{2\times 8}\\\\\Rightarrow t=\dfrac{16\pm \sqrt{320}}{16}\\\\\text{Neglecting negative value of t}\\\\\Rightarrow t=\dfrac{16+17.888}{16}=2.11\ s$