The acceleration due to gravity is
ft/sec/sec.
The initial velocity of ball is
ft/s.
ft/sec.
The initial height when ball is thrown up is
feet.
ft.
Acceleration of a ball is rate of change in velocity
.
Velocity is
.
.
Substitute
in
.

The position of a ball at time
is
.
Velocity of a ball is rate of change in position
.
Position at time
is
.

.
Substitute
in
.

Substitute
.

Substitute
in
.
.
The ball reaches maximum height when velocity is zero.
\
The ball reaches maximum height when time
sec.
The position of ball when time
sec is,

The maximum height of ball is
ft.
The maximum height of ball is
ft.