Answer:
The ball hit the ground at t=6 seconds
Explanation:
we have
![f(t)=-16t^2+96t](https://img.qammunity.org/2021/formulas/mathematics/high-school/m4c6sdohaaeto5y533t02mte7yvrnu0kbj.png)
where
f(t) is he height of the ball in feet
t is the time in seconds
we know that
When the ball hit the ground, the height of the ball is equal to zero
so
For f(t)=0
![-16t^2+96t=0](https://img.qammunity.org/2021/formulas/mathematics/college/ylnjhf7ms003oevs7gzsv4e6l4wy8x2vt4.png)
solve for t
Factor the leading coefficient -16t
![-16t(t-6)=0](https://img.qammunity.org/2021/formulas/mathematics/high-school/30v0i1utmp75un2i4xu6nblievbsmp2dvt.png)
the solutions are
t=0, t=6
Remember that
For t=0 ----> f(t)=0 is the initial height of the ball
Fort=6 sec ----> f(t)=0
therefore
The ball hit the ground at t=6 seconds