What does the slope represent for force vs product of charge?

[mangofries]

Homework Statement

What does the slope represent for a graph of force of electrostatic (y-axis) as a function of product of charge (x-axis)?

-charges are not given - the experiment was done by charging 1 sphere, touching it with sphere two so that each sphere is 1/2 q. By touching sphere 1 with sphere 3, sphere 1 gets a charge of 1/4 while sphere 2 still has a charge of 1/2 (how charge was manipulated). These "coefficients" were graphed on the x-axis.
my slope equals 8.57 x 10^-4 N/q^2, not sure what it represents

Homework Equations

Fe=kq^2 / r^2

The Attempt at a Solution

I set up the equation as:

Fe = 8.57 x 10^-4 N/q^2 q1q2 = kq1q2/r^2
=8.57 x 10^-4 N/q^2=k/r^2
not sure how to end or if this is the right track at all.

any suggestions/answers?

 

[Delphi51]

Welcome to PF!
It looks like you graphed F vs q² and you are comparing with F = kq²/R².
R should have been kept constant as q² was varied.
If so, the formula F = kq²/R² becomes F = constant*q².
This is like y = mx in math, since you have q² on the x axis.
So you should expect a straight line graph whose slope = m = k/R².