Suppose a toy rocket is launched vertically upward from ground level with an initial velocity of 128 feet per second. If air resistance is ignored, the rocket's h height after t seconds is given by the equation h = ?16t2 + 128t. How long will the rocket's flight last?

8 sec

Step-by-step explanation:

h = - 16t² + 128t

how many seconds will go by before the rocket's flight last.

That means we need to find time 't' when the rocket's height h (t) = 0

Therefore,

0 = - 16t² + 128t

Solving for 't'

0 = t (-16t + 128)

0 = t OR 0 = - 16t + 128

0 = t OR - 128 = - 16t

0 = t OR - 128/-16 = t

0 = t OR 8 = t

t=0 is not possible because this would mean that rocket hasn't left the ground.

Thus, the rocket's flight will last for 8 sec.