## Nick2019 3 years ago Frank kicks a soccer ball off the ground and in the air with an initial velocity of 30 feet per second. Using the formula H(t) = −16t2 + vt + s, what is the maximum height the soccer ball reaches? 14.1 feet 13.7 feet 13.2 feet 15.2 feet

1. zepp

We are looking for the highest point of a facing down parabola, therefore the vertex of the parabola.

2. zepp

|dw:1341586592338:dw|

3. SmoothMath

4. Nick2019

so this means??

5. Nick2019

lol i should have read the chapter :/

6. zepp

|dw:1341586632841:dw|

7. zepp

Oh

8. SmoothMath

GAHAHAHA YEEEESSSS

9. Nick2019

lol so whats the answer, nice drawing

10. SmoothMath

The eeeeye, it sees everything!

11. Nick2019

lol i moved my webcam away from me haha

12. zepp

H(t) = −16t2 + vt + s Represents the equation of your parabola, we are looking for the vertex, the x-value of the vertex could be found by using the formula $\frac{-b}{2a}$

13. Nick2019

so one of these 14.1 feet 13.7 feet 13.2 feet 15.2 feet

14. zepp

Now, 30 feet per second. v=30 H(t) = −16t2 + 30t + s

15. zepp

Use the formula I wrote above :)

16. Nick2019

dont know how to solve that :/ i just need the answer no offence

17. Nick2019

ok il guess thanks for the help (in a good way)

18. zepp

A quadratic equation is $$ax^2+bx+c$$ Where the x of the vertex is at $$\large \frac{-b}{2a}$$ In our equation H(t) = −16t2 + 30t + s b is 30 and a is -16 $\frac{-30}{2(-16)}=\frac{-30}{-32}=\frac{30}{32}$

19. zepp

What you have to do next it to replace this x-value back into the equation to find the height (y-value) And sorry I'm at work so I was afk :(

20. Sav_1012

what is it