When the ball is thrown upward, it goes in parabolic path.

The function of height is .

At, initial velocity and initial height 128ft. \ \

.

A)

we can get the maximum height by changing this standard parabolic path into vertex form.

it is in the form , so here vertex .

So, the maximum height that the ball reached is 324ft.

B) The time taken to ball to hit the ground is

At the time of ball hitting the ground, the height of the ball is zero.

                 (The time is not negative) \ \

It reaches the ground after 8 sec.