How do I Calculate V(ab) from E if A(-8,3,2) and B(5,2,3)?

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Homework Help Overview

The discussion revolves around calculating the potential difference V(ab) given an electric field E and two points A(-8,3,2) and B(5,2,3). The electric field is expressed in terms of its components, and the problem involves evaluating a line integral to find the potential difference.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants discuss the setup of the integral for V(ab) and question the limits of integration. There is uncertainty about whether to use the coordinates directly or to consider distances. Some participants also explore the implications of the electric field being conservative and the necessity of checking the curl of the electric field.

Discussion Status

There is ongoing exploration of the problem with various interpretations of the electric field's properties. Some participants have suggested checking if the electric field is conservative, while others are attempting to clarify the correct approach to setting up the integrals. No consensus has been reached, but there are indications of productive discussion regarding the implications of the field's characteristics.

Contextual Notes

Participants note that the problem does not provide explicit information about the path or additional constraints, leading to questions about the assumptions being made regarding the electric field and the integration process.

NWNINA
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Homework Statement


Calculate V(ab) if E = (-5 y / x^3) ax + (5/x) ay + 4 az V/m.
A(-8,3,2) and B(5,2,3).


Homework Equations



Vab=-∫Edl


The Attempt at a Solution



So I tried

V=-[∫(-5y/x^3)dx {from 5 to -8}+ ∫(5x)dy {from 2 to 3} + ∫4dz {from 3 to 2}]

The problem is that the limits are wrong. What should I do?
Should it be the distance and not the literal point on the plane? like the first one, should it be 0 to 13, the second one 0 to 1, the third one 0 to 1?
and what do I do with the remaining variables after the integration. For ex, in the first one I would have a y and on the second one a x
 
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Check if the electric field is conservative. If it is not, the work between a and b depends on the path, and potential is not defined.

ehild
 
ehild said:
Check if the electric field is conservative. If it is not, the work between a and b depends on the path, and potential is not defined.

ehild

It doesn't say anything about this.
 
Potential exist if the curl of the electric field is zero. Have you heard about that?
If not, check if you copied the formulas for E correctly, or any path is given in the problem. If you were supposed to integral for the path you used, note that when determining the integral for a line segment, the initial and final values of all variables have to been substituted. See figure.

ehild
 

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ehild said:
Check if the electric field is conservative. If it is not, the work between a and b depends on the path, and potential is not defined.

ehild

I ended up reading a lot from the book, and yes it is conservative.
The book is just theory no example. So I don't really know the correct approach for this.
I think I'm going to go with V=-[∫(-5y/x^3)dx {from 5 to -8}+ ∫(5x)dy {from 2 to 3} + ∫4dz {from 3 to 2}]

and at the end, where I'm left with variables, substitute them for the coordinates from A
 
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NWNINA said:
I ended up reading a lot from the book, and yes it is conservative.

The z component of the curl is not zero, so it is not conservative.

NWNINA said:
The book is just theory no example. So I don't really know the correct approach for this.
I think I'm going to go with V=-[∫(-5y/x^3)dx {from 5 to -8}+ ∫(5x)dy {from 2 to 3} + ∫4dz {from 3 to 2}]

and at the end, where I am left with variables, substitute them for the coordinates from A

The integral for the first line segment goes from (5,2,3) to (-8,2,3) (red line in the figure). The second integral goes from (-8,2,3) to (-8,3,3) (the blue line) and so on. You have to substitute the values of all variables.

ehild
 

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