Colombo's Law Gizmo - Force & Distance Equation

[garr6120]

Homework Statement

Write the equation that you determined from your results that shows the relationship between F and d for two charged objects.

Homework Equations

The Attempt at a Solution

I have determined a constant value that relates force to separation distance. The value is 8500 N/m^2
I'm assuming the equation is (8500 N/m^2)/r^2, where the 8500 N/m^2 is equal to the two charges and coloumb's constant multiplied together. and r is the distance between the two charges.

 

[andrevdh]

Did you draw a F versus 1/d² graph with your data?

 

[garr6120]

First I drew F vs. 1/d graph which gave me a hyperbola and then my F vs. 1/d^2 graph gave me a linear line and i have calculated the slope of that linear line to be 8500 which has some percent error.

 

[andrevdh]

Yes, that shows that the relationship between F and 1/d² is
linear or that there is a directly proportional relationship if the y-intercept
is close to zero Newton. The gradient is then the proportional constant,
which you determined as 8500. Have a careful look at its unit though.
The empirical equation (supply the units of your constant in the brackets)
is then
F = 8500 ( ) 1/d² or r²

 

[garr6120]

For it's units i get N/m^2 but when i actually multiply coulomb's constant and both q's together i get units of Nm^2 my slope should have the same units as the actual theoretical k.

 

[andrevdh]

The units of the independent variable is per meter square. So the units of the gradient will be N/m^-2 which comes to Nm²