The equation is h(t) = at^2 + vt + d
where a = acceleration of gravity = - 32.174 ft/sec^2
v = 25 feet/sec
d = starting height = 0
and h(t) = 0 when the ball hits the ground.
So, 0 = - 32.174t^2 + 25t + 0
You can use the quadratic formula on that if you want, or you can solve like this:
0 = - 32.174t^2 + 25t
0 = t ( -32.174t + 25)
So, one solution of that is t = 0, corresponding to the initial time when the ball is kicked.
The other time is: 25 = 32.174t
t = 25/32.174 = 0.777 seconds
or approximately 0.8 seconds.
