Relatively simple vectors question, but no numbers....

AI Thread Summary
The discussion revolves around calculating the net force on point charge C due to two identical point charges A and B, using vector principles. The user correctly identifies that the forces exerted by A and B on C cancel each other out in the x-axis, leading to a focus on the y-axis components. They express the net force on C using the superposition principle and explore the relationship between the forces and the angles involved. The conversation highlights the equivalence of certain mathematical expressions, specifically involving the square root of 2, in simplifying the calculations. Overall, the thread emphasizes understanding vector components in electrostatics without directly involving charge values.
Bagwan
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The unit right now is electrostatics, but this question is really just vectors, nothing to do with charges or anything... anyways here is the info:

1. Homework Statement

Three identical point charges, A, B, and C are located as shown here:

M9bYJ9L.png


The force A-on-C is the same as the force B-on-C. What is the net force on C?

Homework Equations



I think the only equation I need is the superposition of force principle:
FnetC = FAonC + FBonC

The Attempt at a Solution


[/B]
Breaking into components (not allowed to use cosine law for some reason):

I know X-axis force is 0 as the 2 forces cancel out (since they are both equal and in opposite directions).

FnetCY = FAonC * cos(45) + FBonC * cos(45)

Not sure what else I can do though...

EDIT: I messed around with the 1-1-sqrt(2) triangle and I'm not sure if this is right, but is (2/sqrt(2)) * FAonC the right answer?

EDIT 2: Yes, that's the right answer, but sqrt(2) * FAonC is also right.

Because guess what, 2 divided by squareroot(2) is THE SAME THING AS squareroot(2)...
 
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seems okay to me
 
assuming the charges on the charges on the corners A and B are all the same polarity
 
rpthomps said:
assuming the charges on the charges on the corners A and B are all the same polarity

Yeah they are all identical.

rpthomps said:
seems okay to me

How would I use the 1-1-squareroot2 triangle to simplify it more? I'm not sure how to do that part too well.
 
replace your cos45 statement with the equivalent ratio
 
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