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Where can a third charge +Q be placed so that it experiences a zero force?

  • Thread starter shashaeee
  • Start date
I'm having a hard time trying to picture the problem:

A charge of +2q is placed at the origin and a second charge of -q is placed at x= 3.0cm. Where can a third charge +Q be placed so that it experiences a zero force?

Here is how I picture the problem:

physics4.jpg
 

berkeman

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I'm having a hard time trying to picture the problem:

A charge of +2q is placed at the origin and a second charge of -q is placed at x= 3.0cm. Where can a third charge +Q be placed so that it experiences a zero force?

Here is how I picture the problem:

View attachment 49498
The 3rd charge could end up anywhere on the line, left, right or between the first 2 charges. What is the equation for the electric field E generated by a charge at some distance...?
 
For Force its, F = KQQ/r2

The way I understand the problem is it could either be on the left or right of those two charges. Because if it was in the middle, the third charge will experience a net force directed to the right. Right?
 

berkeman

Mentor
54,908
5,152
For Force its, F = KQQ/r2

The way I understand the problem is it could either be on the left or right of those two charges. Because if it was in the middle, the third charge will experience a net force directed to the right. Right?
Yes, that is correct. It's good that you see that.
 

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