Find the Y component of Electric field at a point

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Homework Help Overview

The discussion revolves around calculating the electric field at a point due to a charged vertical rod. The problem involves determining the y-component of the electric field at a specified point, given the length of the rod, total charge, and distance from the rod.

Discussion Character

  • Mixed

Approaches and Questions Raised

  • Participants explore the calculation of the electric field components using trigonometric functions and integration. There are attempts to clarify the charge distribution along the rod and the implications for the electric field at point P. Some participants express confusion regarding the correct application of trigonometric functions and integration techniques.

Discussion Status

The discussion is ongoing, with participants sharing various attempts and questioning the assumptions made in their calculations. Some guidance has been provided regarding the need for integration and the use of linear charge density, but no consensus has been reached on the correct approach or solution.

Contextual Notes

Participants note that the problem requires the use of calculus for integration, and there is a discussion about the charge density along the rod. Some participants express frustration with the complexity of the problem and the requirements for accurate calculations.

  • #31
I just did the integration and got -140677.0588 and that was incorrect.
I had my integral limits from 0 to 0.05 and ∫(kqy(dy)/(a(x^2+y^2)3/2))

used U substitution and was a pretty straight forward integral. not sure what I did wrong here
 
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  • #32
isukatphysics69 said:
I just did the integration and got -140677.0588 and that was incorrect.
I had my integral limits from 0 to 0.05 and ∫(kqy(dy)/(a(x^2+y^2)3/2))

used U substitution and was a pretty straight forward integral. not sure what I did wrong here
It's much more helpful to do the integration using symbols. Plug in the numerical values later. There is virtually no way for anyone to look at the result, −140677.0588 and tell what might be wrong with it. It doesn't even have units.

That is pretty close to being the correct integral.
Having ##\ q\ ## there isn't correct. That should be ##\ \lambda\ ##, the linear charge density.
What is ' a ' ? (It's in the denominator.)
For integration limits, 0 to L .​

What do you get for the integral, prior to substituting the integration limits?.
 
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  • #33
SammyS said:
It's much more helpful to do the integration using symbols. Plug in the numerical values later. There is virtually no way for anyone to look at the result, −140677.0588 and tell what might be wrong with it. It doesn't even have units.

That is pretty close to being the correct integral.
Having ##\ q\ ## there isn't correct. That should be ##\ \lambda\ ##, the linear charge density.
What is ' a ' ? (It's in the denominator.)
For integration limits, 0 to L .​

What do you get for the integral, prior to substituting the integration limits?.
I had 'a' as the length of the entire rod, I will try again
 
  • #34
This is really frustrating but I am staying calm like a monk
 
  • #35
isukatphysics69 said:
I had 'a' as the length of the entire rod, I will try again
Well in that case, that does give you a factor of q/L, which is correct and it's needed because, q/L is λ .

Making that replacement, makes your integral:
∫(kqy(dy)/(L(x2+y2)3/2)) with limits from 0 to L .

In more readable form, using LaTeX that can be written:
##\displaystyle \frac{kq}{L} \int_0^L \frac {y\,dy}{(x^2+y^2)^{3/2}} \,,\ ## where I factored out the constant factors.​
.
 
  • #36
ok I got the answer it is -8700 rounded with sig figs. Thank you @haruspex @SammyS. now I will attempt the x component since I got lucky with that one
 

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