1. Not finding help here? Sign up for a free 30min 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!

Forming Linear Equations From Non-Linear Equations

  1. Nov 10, 2005 #1
    For my first year formal lab im having a little bit of trouble with one aspect, lets see if anyone can help

    Im trying to rearrange the equation

    T = 2pi [(32 L I)/(pi S d^4)]^1/2

    ....(sorry, i dont know how to use the better way of displaying math) to form a linear equation so it can be graphed as a line, but im having a rough time of it. My biggest problem seems to be getting the + b segment (for the form y=mx+b), the + sign doesnt seem to want to show up when the origional equation is all multiplication. Any help would be appreciated.
  2. jcsd
  3. Nov 10, 2005 #2


    User Avatar
    Homework Helper

    Which are variables and which are constants.

    The simplest way of linearising products of things to various powers is simply to take logs.
  4. Nov 10, 2005 #3
    Its an equation relating to a torsional pendulum with a metal disk at the end

    I = moment of inertia for disk
    L = length of suspending wire
    S = shear modulus
    d = diameter of suspending wire
    T = period of rotation

    the constants are S d and I

    i think i need to graph T against L somehow
    Ill give the log thing a shot
    Last edited: Nov 10, 2005
  5. Nov 10, 2005 #4
    how does this sound, checking to see if im in the ball park

    T^2 = {[4 pi (32) I]/(S d^4)} L

    where T^2 = y L = x and everything in {} is m, guessing b doesnt apply here and any intercept on the graph can be attributed to error
    Last edited: Nov 10, 2005
  6. Nov 10, 2005 #5
    That would work provided you don't change the parameters in the { }.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?