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/sci/ - Science & Math

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5756687 No.5756687 [Reply] [Original]

Question from a very naive little sciencer:

http://en.wikipedia.org/wiki/Coulomb's_law#Experimental_verification_of_Coulomb.27s_law

Can someone elaborate to derive the part where it makes the leap and a jump

q^2 / 4 pi esub0 L = mg tan theta1

Thank you.

>> No.5756707
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5756707

Take the line ending with (Coulomb's Law) and substitute equation 3.

>> No.5756715

>>5756707
Yes, but derive
q^2 / 4 pi esub0 L

>> No.5756735
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5756735

>>5756715
>assuming Coulomb's law is correct
I could be wrong but I don't think it's "derived", it's more "experimentally determined" and then used in the example.

>> No.5756737 [DELETED] 

>>5756735
I understand, but how why the operations to the components of the formula the way they are and why does it incorporate 4 pi (assuming radian) and esub0 and the others where they are?

>> No.5756741

>>5756735
I understand, but how/why are the operations to the components of the formula the way they are and why does it incorporate 4 pi (assuming radian) and esub0 and the others where they are?

>> No.5756759
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5756759

>>5756741
q^2 (which should be q1*q2) and 1/(L^2) come from the observations that form the basis for the law:
>the magnitude of the Electrostatics force of interaction between two point charges is directly proportional to the scalar multiplication of the magnitudes of charges and inversely proportional to the square of the distances between them

1/(4*pi*e_0) is Coulomb's constant (http://en.wikipedia.org/wiki/Coulomb%27s_constant)) and as far as I've been taught it's just to keep your units in check in the SI system but it could very well have more behind it than that.