1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Type of curvature of gradient force from edge to center of a sphere

  1. Jun 5, 2013 #1
    I was doing some simple physics with a ball resting on a table and I made this curve

    (0,0) (25, 6.8) (50, 27.51) (75, 63.4) (100, 112.34) (125, 175.7) (150, 253.3) (175, 345.4)

    I was wondering if anyone could identify what sort of curve it is? I am just curious.

    This is not a homework problem.
  2. jcsd
  3. Jun 5, 2013 #2


    User Avatar
    Staff Emeritus
    Science Advisor
    Education Advisor

    Why can't you plot this out, post it here, and tell us what you think?

  4. Jun 5, 2013 #3
    I got the points off of a curve that developed due to the the apparent force of gravity pushing a sphere down on a table...I cant tell if it is hyperbolic or parabolic...or maybe a section of an ellipse(if thats even different)...I have seen the curve and I am guessing it is a parabola but I am not sure how to be certain because I could do a quadratic regression in my calculator but that wouldnt really prove anything would it?
  5. Jun 5, 2013 #4
    Here is a picture of the curve


    Hyperbole, Parabola, or a section of ellipse I cant tell the difference
  6. Jun 5, 2013 #5


    User Avatar
    Science Advisor

    I did a curve fit on Excel
    The ordered pairs you gave at the beginning lie very close to a perfect parabola:
    y = 0.011329238095238*x^2 - 0.009373809523815*x - 0.037083333332703
    with R^2 of 0.999997
  7. Jun 5, 2013 #6
    Thanks man, I wonder why the force over the gradient of the circle translates proportionally into a practically perfect parabola?

    I will have to do some more investigating!

    Thanks again for your reply.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook