How Can Visualizing Magnetic Forces on Current Enhance Understanding?

Click For Summary

Homework Help Overview

The discussion revolves around visualizing magnetic forces acting on current-carrying wires, particularly in relation to their arrangement and the resulting forces. The subject area includes concepts from electromagnetism and magnetic force calculations involving parallel wires.

Discussion Character

  • Exploratory, Assumption checking, Conceptual clarification

Approaches and Questions Raised

  • Participants explore different visualizations of wire arrangements and question the implications of those arrangements on magnetic force calculations. There is discussion about the relevance of the cosine law and the conditions under which it applies.

Discussion Status

The conversation is ongoing, with participants providing clarifications and insights regarding the geometric arrangements of the wires and their effects on the magnetic forces. Some participants express confusion about the differences between similar problems, indicating a productive exchange of ideas.

Contextual Notes

Participants mention constraints such as the specific distances between wires and the requirement for certain arrangements to apply particular mathematical principles. There is also a reference to the need for visual aids in understanding the problem setup.

fight_club_alum
Messages
63
Reaction score
1
Homework Statement
Three long, straight, parallel wires all lie in the yz plane and each carries a current of 20
A in the positive z direction. The two outer wires are each 4.0 cm from the center wire.
What is the magnitude of the magnetic force on a 50-cm length of either of the outer
wires?
answer is 1.5 mN
Relevant Equations
f12 (l) = (uo * i1* i2)/(2pi * r)
243775

This is how I visualize the problem (of course I am drawing this as if it is in the z-y axis); I don't know what will be the next step. Anyone please help me.
Thank you
 
Physics news on Phys.org
I don't see how the wires could be in a triangular arrangement if they all lie in the same plane. I'd imagine it'd something more like this:

243779


Edit: By the way, your Relevant Equation, as stated, gives the force per unit length of the parallel wires.
 
  • Like
Likes   Reactions: JD_PM and fight_club_alum
hey, thank you for replying to my question
If I put them that way they won't give 1.5 mT and I don't think we can use the cosine law in that case
 
fight_club_alum said:
hey, thank you for replying to my question
If I put them that way they won't give 1.5 mT and I don't think we can use the cosine law in that case
No need to use the cosine law. Check out my edit to my post above.
 
  • Like
Likes   Reactions: fight_club_alum
Aren't those wires parallel, and the length is 50 cm?
 
fight_club_alum said:
Aren't those wires parallel, and the length is 50 cm?
The wires are "long" and parallel. You're only concerned with a 50 cm segment of each of the outer wires.
 
  • Like
Likes   Reactions: fight_club_alum
gneill said:
The wires are "long" and parallel. You're only concerned with a 50 cm segment of each of the outer wires.
does it give that answer if you do so? if Yes, can you tell the difference between this question and that question, please: Three long, straight, parallel wires each carry a current of 10 A in the positive x-direction. If the distance between each wire and the other two is 10 cm, what is the magnitude of the magnetic force on a 20-cm length of either of the wires?
Because that way doesn't give the answer in both and I, honestly, can't find a difference?
(note: for the second question, I had to draw an equilateral triangle and use the cosine law)
 
fight_club_alum said:
does it give that answer if you do so?
Yes.
if Yes, can you tell the difference between this question and that question, please: Three long, straight, parallel wires each carry a current of 10 A in the positive x-direction. If the distance between each wire and the other two is 10 cm, what is the magnitude of the magnetic force on a 20-cm length of either of the wires?
There they specify that the distances between all the wires is the same: 10 cm. That forces a triangular arrangement and they will not all lie in the same plane.
 
  • Like
Likes   Reactions: fight_club_alum
gneill said:
Yes.

There they specify that the distances between all the wires is the same: 10 cm. That forces a triangular arrangement and they will not all lie in the same plane.
Yes, I understand now what is happening
Thank you so much for clarifying; after the first couple of questions, all involved a triangular arrangement I thought these questions can't be solved without the cosine law!
Thank you so much again for clarifying
 
  • #10
Glad I could help!
 
  • Like
Likes   Reactions: fight_club_alum

Similar threads

Replies
4
Views
1K
  • · Replies 4 ·
Replies
4
Views
3K
  • · Replies 9 ·
Replies
9
Views
2K
Replies
12
Views
2K
Replies
1
Views
2K
Replies
7
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K
Replies
5
Views
2K
  • · Replies 12 ·
Replies
12
Views
2K