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Posts posted by Disclaimer

  1. Criminals are going to carry guns everywhere... so why not law-abiding people?

    I guess I'm feeling exceptionally libertarian today, so Darwin and I think we'd be willing to risk the few 'accidents' from careless gun owners or gun owners that abused alcohol in order for the rest of the people that feel they should have the right to carry, to carry. Dorms and all.

  2. You have the equation correct, but the answer is wrong. LOL. Not quite sure what you did there. Make sure you get the square root of 2 first, then multiply by 17500. The correct answer is 24748.7 MPH.

    I plugged it into Excel like this: =17500*SQRT(2)... so? Maybe I looked at the wrong cell? I just quick plugged it into to the sheet I was working on other stuff with. I get Casper's number this time. :dunno:

    Really close. Really, really close. First, yes the center of the earth is the origin. If you look, x and y are even labeled in the image. The Vertex is (0,4100). According to the image, the graph of the parabola opens down, so p has to be negative. You know p is 4100, as it's given to you.

    I remembered to put the parabola negative (-x), but I goofed when I put the vertex at -4100, hence why my original answer has a wrong sign for the intercept. Good catch.

    I should've caught it when I plugged the equation in here to check: http://webgraphing.com/graphing_basic.jsp, but it puts the x-axis on the bottom regardless of where your y-axis is, so I missed it.

  3. a) 17500*SQRT(2) = 24041.6 mph

    b) Assuming the center of earth is the origin (and they're asking for the equation of the orbiting satellite, not the one that flies off into space), in Cartesian coordinates, the equation of a circle is x^2+y^2=r^2, so with the earth being 4100 miles. it's x^2+y^2=4100^2.

    But if they want the parabola --

    f26.gif

    4(4100)(y+4100)=-(x^2)

    16400y+4*4100^2=-x^2

    16400y=-x^2-4*4100^2

    y = -x^2/16400-4100

    Valid for domain x = 0+

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