Find Potential Minimum of Two Point Charges

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Homework Help Overview

The problem involves two point charges, one located at the origin and the other at a specified distance along the x-axis. The objective is to determine the point along the x-axis where the electric potential is minimized.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • The original poster expresses uncertainty about how to begin the problem and seeks assistance. Some participants question the necessary conditions for finding the minimum potential, particularly regarding the derivative of the potential function.

Discussion Status

Participants are exploring the mathematical relationships involved in calculating the potential and its minimum. A hint regarding the derivative being zero as a condition for a minimum has been provided, and one participant has offered a potential formula for the electric potential between the two charges.

Contextual Notes

There is an indication that the original poster may have struggled with the formulation of the problem, as evidenced by an apology for editing their post. The discussion also reflects a need for clarity on the application of derivatives in this context.

Mikesgto
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Homework Statement


A charge of 0.611 nC is placed at the origin. Another charge of 0.383 nC is placed at x1 = 8.1 cm on the x-axis.
At which point on the x-axis does this potential have a minimum?

Homework Equations


U=(kq1q2)/r

The Attempt at a Solution


I really have no idea how to even start this problem. I've been thinking about it for a couple hours now. Any help would be appreciated.

Homework Statement


Homework Equations


The Attempt at a Solution

 
Last edited:
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Post the complete question.
 
I edited the post. My apologies.
 
And also once I messed up enough the hint was that
"A necessary condition for the potential to have a minimum is that its derivative is 0."

But the derivative of what? The only thing I can think of is the V(r)=kQ/r
 
Potential at a point distance x from q1 is given by

V = k*q1/x + k*q2/(d-x) where d is the distance between the charges.

To find the minimum potential between the charge, find dV/dx and equate it to zero.
And find x.
 
Thanks a lot! It was kind of a messy derivative but I am so thankful you helped me out. :)
 

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