Why does x1i =r1 -y1j in Lorentz electromagnetic force?

  • Context: Undergrad 
  • Thread starter Thread starter retupmoc
  • Start date Start date
  • Tags Tags
    Electromagnetism
Click For Summary

Discussion Overview

The discussion revolves around the expression x1i = r1 - y1j in the context of the Lorentz electromagnetic force, as presented in a physics electromagnetism course. Participants are exploring the definitions and relationships between the variables involved, particularly in relation to vector notation and the application of the Pythagorean theorem.

Discussion Character

  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • One participant expresses confusion regarding the expression x1i = r1 - y1j, questioning whether it derives from the Pythagorean theorem and whether the quantities should be squared.
  • Another participant clarifies that the vector r is defined as r = xi + yj, emphasizing the distinction between the vector and its magnitude.
  • A later reply indicates that the initial confusion was resolved, acknowledging the clarification provided.
  • Another participant poses a follow-up question regarding the expression vy1k = v x r, seeking further explanation.

Areas of Agreement / Disagreement

Participants generally agree on the definitions of the vectors involved, but the discussion remains unresolved regarding the specific expression vy1k = v x r, as it has not yet been clarified.

Contextual Notes

There may be limitations in understanding due to the reliance on visual figures from the referenced material, which are not included in the discussion. Additionally, the relationship between the variables and their definitions may depend on specific assumptions that are not fully articulated.

retupmoc
Messages
47
Reaction score
0
When going over my notes on the lorentz electromagnetic force in my physics 3 electromagnetism class got a bit puzzled by one statement that seems just to be taken for granted. Could anyone help me and tell me why x1i =r1 -y1j on page 5 on http://www.physics.gla.ac.uk/~dland/ELMAG305/Elmag305txt1.pdf where frame 1 is the stationary frame and 2 the frame moving with velocity v to the right of frame 1

If its just by using pythagorus wouldn't the above quantities (x,y and r) be to the second power. i just can't get my head around this and realize its probably something really straight forward. any help would be much appreciated.
 
Last edited by a moderator:
Physics news on Phys.org
the vector r = xi + yj by definition, see the figure on the previous page.

Using the Pythograean theorem you get the magnetude of r.

[tex]\mid \hat {r} \mid = \sqrt { x^2 + y^2 }[/tex]

You are dealing with the VECTOR r. See the difference?
 
Last edited:
haha yeah i do now and realize how obvious that was, thanks
 
Another quick question, why on page 6 of the slide does vy1k = v x r?
 

Similar threads

Undergrad [Q] Lorentz force in momentum conservation view
  • · Replies 9 ·
Replies
9
Views
2K
Undergrad Confused about electromotive forces
  • · Replies 10 ·
Replies
10
Views
2K
Undergrad Two ways of constructing electromagnetism, which is correct?
  • · Replies 7 ·
Replies
7
Views
2K
Undergrad Permanent Magnetic Dipole in an electromagnetic field
  • · Replies 2 ·
Replies
2
Views
2K
Undergrad Magnetic Lorentz Force: Questions & Answers
  • · Replies 4 ·
Replies
4
Views
2K
Undergrad The implications of symmetry + uniqueness in electromagnetism
  • · Replies 1 ·
Replies
1
Views
2K
Undergrad What is the origin of Lorenz force?
  • · Replies 5 ·
Replies
5
Views
2K
Undergrad Magnetic field as result of length contraction
  • · Replies 20 ·
Replies
20
Views
5K
Undergrad Why is the Lorentz Force always perpendicular to velocity?
  • · Replies 55 ·
2
Replies
55
Views
6K
Undergrad Net magnetic force in discontinuous circuits?
  • · Replies 6 ·
Replies
6
Views
815