hey can someone help me with the question below i will medal

Question

hey can someone help me with the question below  i will medal

anonymous · Answer

I dont have any idea how to do this

Arianna kicks a soccer ball off the ground and into the air with an initial velocity of 42 feet per second. Assume the starting height of the ball is 0 feet. Approximately what maximum height does the soccer ball reach? 
 	
	1.3 ft
	2.6 ft
	26.0 ft
	27.6 ft

anonymous · Answer

can you help me

igreen · Answer

Hmm..there's a formula for this..

igreen · Answer

It's something like $\sf H(t) = -16t^2 + vt + s$

anonymous · Answer

so how do you solve it?

igreen · Answer

We plug in the initial velocity(v) and the starting height(0).

$\sf H(t) = -16t^2 + vt + s$

$\sf H(t) = -16t^2 + 42t + 0$

or

$\sf H(t) = -16t^2 + 42t$

igreen · Answer

Now, we want to find the maximum height which is the same as the y-value of the vertex.

Formula to find the x-value of a parabola:

$\sf\dfrac{-b}{2a}$

Our equation is in the form of:

$\sf ax^2 + bx + c$

igreen · Answer

So in this case, 'a' is equal to -16, and 'b' is equal to 42.

igreen · Answer

$\sf\dfrac{-42}{2(-16}$

Simplify that

igreen · Answer

(-16)

anonymous · Answer

wouldnt it be -42/-32

igreen · Answer

Yes, now divide that.

anonymous · Answer

1.3125

anonymous · Answer

so what do i do now

anonymous · Answer

thanks

igreen · Answer

Yes, now plug that back into the equation for 'x' or 't' in this case:

$\sf H(t) = -16t^2 + 42t$

$\sf H(t) = -16(1.3125)^2 + 42(1.3125)$

Simplify

igreen · Answer

No, that's incorrect..

igreen · Answer

Sorry, my internet just went out for a minute there.

anonymous · Answer

oh ok so what do i do wit that then

igreen · Answer

Well, first simplify $\sf (1.3125)^2$

anonymous · Answer

1.7226563...

anonymous · Answer

is the answer D

igreen · Answer

Yep, you got it.

anonymous · Answer

thanks   do you think that you could help me with another one in a new thread

igreen · Answer

$\sf H(t) = -16t^2 + 42t$

$\sf H(t) = -16(1.3125)^2 + 42(1.3125)$

Simplify the exponent:

$\sf H(t) = -16(1.72265625) + 42(1.3125)$

Multiply:

$\sf H(t) = -27.5625 + 55.125$

Add:

$\sf H(t) = 27.5625$

$\sf H(t) \approx 27.6$

igreen · Answer

Sure thing, I might be able to help.

anonymous · Answer

ok thanks