## anonymous one year ago Fan and medal HELP PLEASE !! When a ball is thrown, the path it travels is a parabola. Suppose a baseball is thrown from ground level, reaches a maximum height of 50 feet, and hits the ground 200 feet from where it was thrown. Assuming this situation could be modeled on a coordinate plane with the focus of the parabola at the origin, find the equation of the parabolic path of the ball. Assume the focus is on ground level. ?

1. anonymous

|dw:1442354060646:dw|

2. anonymous

can you explain how I can find the equation, this confused me a lot :(

3. anonymous

Hmm... let's try drawing it on a coordinate plane. |dw:1442354849953:dw|

4. anonymous

So you're given: $\sf \text{focus}~=~(0,0) \\ \text{vertex}~=~ (0,50) = (h,k) \\ p = 50 : (\text{distance between the vertex and the focus, or focus and directrix})$$4p(y-k)=(x-h)^2$

5. anonymous

Are you able to solve this now?

6. anonymous

Oh, sorry, meant to say that: p is the distance from focus to vertex, or VERTEX to directrix. These two relations make the directrix equidistant from the vertex, and the vertex equidistant from the focus.

7. anonymous

okay thank you I understand now :)

8. anonymous

Wonderful!