I need help ASAP! (pre-calculus)

dancequeen619

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Oct 26, 2005
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Here's the problem:
A baseball player tries to hit a ball over an outfield fence that is 4 m high and 110 m away from home plate. The highest point of the baseball's path is 30 m high and 60 m from home plate.

a) If home plate is at the origin of a coordinate system, find an equation of the parabolic path of the baseball.

b) Will the ball go over the outfield fence for a homerun? Justify

c) How far from home plate would the ball land if there was no obstruction?

I don't need the answer, I just need to know how to do it. Thanks!
 
You are given that the vertex of this negative parabola is at (h, k) = (60, 30), and that a (desired) point on the parabola is at (x, y) = (110, 4).

a) They seem to be saying that the ball will be starting at (x, y) = (0, 0). Of course, this is impossible, since you can't hit a home run if the ball is in the dirt. But, as long as you make this erroneous assumption clear, you should be okay using (x, y) = (0, 0).

Plug h, k, x, and y into the vertex form, y = a(x - h)<sup>2</sup> + k, of the parabola. Solve for "a". Rewrite the equation with the known values of h, k, and a.

b) If you plug "110" in for "x", do you get y > 4?

c) When y = 0, what is x?

Hope that helps a bit.

Eliz.

P.S. Algebra questions should be posted to one of the "algebra" categories. Thank you.
 
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