How do electrical charges attract/repel each other

  • Context: High School 
  • Thread starter Thread starter DrKARMA
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Discussion Overview

The discussion revolves around understanding the forces between electrical charges, specifically in a scenario involving three charges and how to determine the resultant force on one of them. The focus is on the application of concepts related to attraction and repulsion of charges in a physics homework context.

Discussion Character

  • Homework-related

Main Points Raised

  • One participant expresses confusion about the direction of forces acting on a charge due to the presence of two other charges, indicating a misunderstanding of vector directions.
  • Another participant suggests that to find the resultant vector on charge C, one must consider the directions in which charges A and B are pulling on it, rather than the direction charge C is pulling on them.
  • There is a suggestion that charge C is attracted towards both charge A and charge B, leading to a resultant vector that is directed left and slightly down.

Areas of Agreement / Disagreement

The discussion reflects some agreement on the concept that opposite charges attract, but there is uncertainty regarding the specific directions of the vectors and the resultant force on charge C. The participants do not reach a definitive conclusion on the correct vector direction.

Contextual Notes

Participants do not clarify the assumptions regarding the magnitudes of the charges or the specific distances involved, which may affect the resultant force calculations.

DrKARMA
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Ok. I understand like repel and opposite attract. There are these physics homework with 3 charges and find the force from 2 of them on one. I understand the math: the only problem is my signs are wrong due to not understanding the direction of the force.

For example,
There's a positive charge (A) on origin. There's a positive charge (B) 4 meters up. There's a neg charge (C) 3 meters x-axis and 4 meters y axis. Find the resultant vector on charge 3?

For me, I would make charge 3 my main object. It would then attract and pull Charge B, making a vector to the SOutheast. It would then pull charge A to the NE direction. Then the resultant vector would be to right. But I am wrong.


I am literally confused. I do not know which direction to draw the vectors pointing. Please help. Thank you in advance.
 
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If you're trying to find the vector of charge C, then you need to find out which direction the other 2 charges are pulling on it, not which way charge C is pulling the other two.
 
So the resultant is to the left?
 
DrKARMA said:
So the resultant is to the left?

If opposite charges attract, then charge C is attracted towards charge B, correct?
And it also is attracted towards charge A.
Since both A and B are to the left of C, I'd say that is correct. It should have a vector left and a little down.
 
Alright thanks. I think I get it now
 

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