Force on a point charge near a uniformly charged rod

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Homework Help Overview

The discussion revolves around the calculation of the force on a point charge located near a uniformly charged rod. Participants are examining the setup of the integral used to determine this force, focusing on the correct interpretation of variables involved.

Discussion Character

  • Mathematical reasoning, Assumption checking

Approaches and Questions Raised

  • One participant points out a potential error in the setup of the integral, suggesting a need to distinguish between the constant length of the rod and the variable of integration. There is an emphasis on ensuring contributions from the entire rod are considered.

Discussion Status

Participants are engaged in clarifying the mathematical setup of the problem. Guidance has been offered regarding the use of LaTeX for posting equations, indicating a supportive environment for learning. There is an acknowledgment of the original poster's willingness to improve and share results in the future.

Contextual Notes

There is a mention of the need for clearer mathematical representation and the importance of correctly setting up the limits of integration, which may affect the understanding of the problem.

athenad07
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Homework Statement
The charge per unit length on the thin rod shown here is What is the electric force on the point charge q? (See the preceding problem.)
Relevant Equations
here are the solution that I calculated, and I use the equation that E field equal to Force among charges over charges, but it yield quit different answer than the correct answer.
Screenshot 2024-10-27 at 15.14.04.png
Screenshot 2024-10-27 at 15.15.41.png
IMG_9426.JPG
IMG_9427.JPG
 
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This equation is set up incorrectly.

Screen Shot 2024-10-27 at 2.41.08 PM.png

  1. You are confusing the constant length of the rod ##l## with the variable of integration ##x##. You should keep the two separate and rewrite the integral.
  2. You want to add contributions from the entire rod, so the lower limit should be at the left end of the rod.
We would appreciate if you used LaTeX to post equations. To learn how, click on the link "LaTwX Guide", lower left, just above "Attach files."

(Edited for typos.)
 
Last edited:
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Okay! I will next time, thank you for the advice. Seems I still have a long way to learn :)
 
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athenad07 said:
Okay! I will next time, thank you for the advice. Seems I still have a long way to learn :)
Post your results when you're ready. We'll be here.
 
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