Electric force and free electrons

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Homework Help Overview

The discussion revolves around the electrostatic equilibrium of a free electron and a free proton in the presence of two fixed point charges, one negative and one positive, located at opposite ends of a meterstick.

Discussion Character

  • Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants explore the conditions for electrostatic equilibrium, questioning whether it is possible for a free electron and proton to achieve this state given the nature of the charges involved.

Discussion Status

There is a general agreement among participants that equilibrium cannot be achieved due to the nature of the forces acting on the charges. Some participants have suggested methods to analyze the forces mathematically, while others confirm the reasoning behind the impossibility of equilibrium.

Contextual Notes

Participants are discussing the implications of having only one positive and one negative charge, questioning the assumptions about the necessity of opposite charges for equilibrium.

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Two point charges of -1.0 micro C and +1.0 micro C are fixed at opposite ends of a meterstick. Where could a) a free electron and b) a free proton be in electrostatic equilibrium?

I'm guessing the answer is nowhere since there have to be opposite charges to be in equilibrium?
 
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I think you are right. The forces don't balance anywhere.
 
is there any way I can prove it with the formula kq1q2/r^2?
 
Put one charge at r=(1/2) and another at r=(-1/2). Then the magnitude (ignoring direction) of the force on the third charge located at x due to one charge is k/(x-1/2)^2 and the other is k/(x+1/2)^2. If you set those equal you find the only possible position is x=0. But at x=0 you know the directions of both forces are the same. So they can't cancel.
 
yes! that's what I thought... thank you!
 

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