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Need help with formula: H(t) = -16^2 + vt + s

Jules kicks a soccer ball off the ground and into the air with an initial velocity of 25 feet per second. Assume the starting height of the ball is 0 feet. Approximately what maximum height does the soccer ball reach?


I know that v=25 and s=0

So now I have:

H(t) = -16^2 + 25t + s

But I have no idea how to find the maximum height.


(I've seen this question posted before and everyone said it needed more information, but this is all the question said)

Verified Answer :

syed514



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.

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