Answer:
t = 4 seconds
Step-by-step explanation:
The height of the projectile after it is launched is given by the function :
t is time in seconds
We need to find after how many seconds will the projectile land back on the ground. When it land, h(t)=0
So,
The above is a quadratic equation. It can be solved by the formula as follows :
Here, a = -16, b = 32 and c = 128
Neglecting negative value, the projectile will land after 4 seconds.