Forming Linear Equations From Non-Linear Equations

In summary, the conversation discusses a problem with rearranging an equation for a first year formal lab. The equation relates to a torsional pendulum with a metal disk and involves variables such as moment of inertia, length of suspending wire, and shear modulus. The goal is to linearize the equation for graphing purposes, and using logs is suggested as the simplest method. The constants in the equation are identified as S, d, and I, and the log equation T^2 = {[4 pi (32) I]/(S d^4)} L is proposed as a possible solution.
  • #1
K - Prime
6
0
For my first year formal lab I am having a little bit of trouble with one aspect, let's see if anyone can help

Im trying to rearrange the equation

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

...(sorry, i don't know how to use the better way of displaying math) to form a linear equation so it can be graphed as a line, but I am having a rough time of it. My biggest problem seems to be getting the + b segment (for the form y=mx+b), the + sign doesn't seem to want to show up when the origional equation is all multiplication. Any help would be appreciated.
 
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  • #2
Which are variables and which are constants.

The simplest way of linearising products of things to various powers is simply to take logs.
 
  • #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
 
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  • #4
how does this sound, checking to see if I am 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 doesn't apply here and any intercept on the graph can be attributed to error
 
Last edited:
  • #5
That would work provided you don't change the parameters in the { }.
 

1. How do I know if an equation is non-linear?

An equation is non-linear if it contains variables with exponents other than 1, or if the variables are multiplied together. For example, y = x^2 + 3x is non-linear because it contains x^2 and x multiplied together.

2. Can any non-linear equation be rewritten as a linear equation?

No, not all non-linear equations can be rewritten as linear equations. Some non-linear equations, such as exponential or logarithmic equations, cannot be written in the form y = mx + b. Only equations with variables raised to the first power and variables that are not multiplied together can be rewritten as linear equations.

3. What is the process for converting a non-linear equation into a linear equation?

The first step is to rearrange the equation so that the non-linear term is isolated on one side. Then, take the derivative of both sides of the equation. The resulting equation will be in the form y = mx + b, where m is the slope and b is the y-intercept.

4. Why would someone want to convert a non-linear equation into a linear equation?

Converting a non-linear equation into a linear equation can make it easier to solve or analyze. Linear equations are simpler and more familiar to work with, so converting a non-linear equation can make it easier to understand and manipulate the equation.

5. Are there any limitations to converting non-linear equations into linear equations?

Yes, there are limitations to this process. As mentioned earlier, not all non-linear equations can be rewritten as linear equations. Additionally, the resulting linear equation will only be an approximation of the original non-linear equation, as the process of taking derivatives introduces some error. This method is best used for simplifying and analyzing non-linear equations, rather than finding exact solutions.

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