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, how long does it take until the soccer ball hits the ground again?

Question

migitmack · Answer

oh man, I hate Pshycics

migitmack · Answer

Physics

anonymous · Answer

$$h(t) = -16t^2 + (Velocity)t + (height)$$

anonymous · Answer

$$0 = -16t^2 + 25t + 0$$
And then you have to factor...hold on a minute

anonymous · Answer

Ok its easier to understand like this:
$$height = -16t^2 + (velocity)t + starting height$$
That is a quadratic equation: 
y = ax^2 + bx + c
0 = -16t^2 + 25t + 0

So you can use the quadratic formula:
$$x = (-b \pm \sqrt{b^2 - 4ac} / (2a)$$

Let's substitute x for t so that the equation is easier to understand:
$$0 = -16x^2 + 25x + 0$$
$$y = ax^2 + bx + c$$ so 
a = -16
b = 25
c = 0
Substitute these into the quadratic formula:
$$x = -25 \pm \sqrt{25^2 - 4(-16)(0)}$$

anonymous · Answer

Now solve what's inside the square root sign:

25^2 = 25 * 25 = 625 

4*-16*0 = 0

625 - 0 = 625.
So now find the sq rt of 625 = 25
\
Now you must solve the formula:
x = -25 + 25   /(2(-16))
x = 0 / -32 = 0
x = 0

x = -25 - 25    /(2(-16))
x = -50 / -32
x = 1.5625



*****So it will take approximately 1.5625 seconds for the ball to hit the ground:)

anonymous · Answer

Hope I helped even though I took so long:D