Point charges and magnitude of the electric field at the center of a triangle

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Homework Help Overview

The problem involves calculating the magnitude of the electric field at the center of an equilateral triangle with point charges placed at each corner. The original poster questions whether this magnitude is greater than, less than, or the same as that at the midpoint of a side of the triangle.

Discussion Character

  • Exploratory, Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants discuss the electric field produced by point charges and the implications of symmetry in the arrangement. There is an exploration of the conditions under which the electric field might be zero, particularly at the center of the triangle versus the midpoint of a side.

Discussion Status

The discussion includes various interpretations of the electric field's behavior due to the arrangement of charges. Some participants suggest that the electric field at the center cannot be zero because of the presence of multiple charges, while others express confusion about the calculations and the implications of symmetry.

Contextual Notes

Participants are working under the assumption that all charges are equal and positive, and there is a focus on the geometric properties of the triangle affecting the electric field. There is also a mention of the original poster's calculation of the electric field magnitude at the midpoint of a side.

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Homework Statement


A point charge q = 4.9 \mu C is placed at each corner of an equilateral triangle with sides 0.20 m in length.
Is the magnitude of the electric field at the center of the triangle greater than, less than, or the same as the magnitude at the midpoint of a side? Explain.


Homework Equations


E = q/r^2


The Attempt at a Solution


I found the magnitude of the midpoint of the triangle to be 1.5e6 but I am not sure how to explain this in words. Any guidance would be appreciated!
 
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well you know that the magnitude of the electric field at the centre of the triangle is 0.
and you also know that that if you have equal charges placed a distance d apart on the line, at d/2 the E field is 0. But in this case there is a third charge on the opposing vertex. So the electric field there cannot be 0. you also know that they are all positive charges. So there you go
 
oh sorry I thought you said you got the magnitude on the side to be 1.5e6.
Well keep trying it until you get 0 at the centre lol
 
oops i meant to say the midpoint of the sides was 1.5e6. sorry!
 
so to put it in stupid people (being me) terms, since we know that the first two point charges (4.9 uC) are positive, and i calculated the third pt charge to be positive, this means that the midpoint of the triangle is zero? so the zero mag is due to the repelling forces among the 3?
 
Yeah, its a property of certain shapes. I think it has something to do with all shapes that have as many symmetrical vertex to midpoint bisects as they do sides all will experience the same 0 force at the centre. The same thing is for gravity right?

Also, that's why circles are ridiculous, because they have infinite sides and infinite symmetrical lines can be drawn through it.
 
ok thanks
 

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