I Calculating Fluke: Subtract A or R?

  • I
  • Thread starter Thread starter Edwardy
  • Start date Start date
AI Thread Summary
Calculating fluke involves understanding the geometric relationships in different scenarios. The subtraction of a from r or vice versa depends on the specific configuration of the triangles involved. In one case, the length of the segment is determined by subtracting 2a from r, while in the other, r is subtracted from 2a. Both cases rely on the principle of similar triangles to establish the necessary relationships. The geometry of the situation dictates which subtraction method is appropriate.
Edwardy
Messages
3
Reaction score
1
I need to calculate fluke.
Why do I in the first picture, when calculating the height, subract a from r, while in the other one, I subract r from a?
What does that depend on?
*I didn't translate the text because it is long and would take me a lot of time to do, but I will do it if it's neceserry.

Screenshot_20230413-094949.jpg

Screenshot_20230413-095006.jpg
 
Physics news on Phys.org
Edwardy said:
Why do I in the first picture, when calculating the height, subract a from r, while in the other one, I subract r from a?
What does that depend on?
In one case, ##\mathbf{2}a## is subtracted from ##r##. In the other case, ##r## is subtracted from ##\mathbf{2}a##.

The reason for the difference is that the geometry is different for the two cases. But, in each case you use similar triangles to set up the relations.

For the first case you have the figure
1681420826750.png

The triangles ABC and DEC are similar. Note that the length of red segment CF is ##r - 2a##.

For the second case you have the figure
1681421093040.png

The triangles ABC and DEC are similar. Note that the length of EC is ##2a - r##.
 
Reply
  • Informative
  • Like
Likes Lnewqban and berkeman

Thread 'How to picture the vector potential?'

Susskind (in The Theoretical Minimum, volume 1, pages 203-205) writes the Lagrangian for the magnetic field as ##L=\frac m 2(\dot x^2+\dot y^2 + \dot z^2)+ \frac e c (\dot x A_x +\dot y A_y +\dot z A_z)## and then calculates ##\dot p_x =ma_x + \frac e c \frac d {dt} A_x=ma_x + \frac e c(\frac {\partial A_x} {\partial x}\dot x + \frac {\partial A_x} {\partial y}\dot y + \frac {\partial A_x} {\partial z}\dot z)##. I have problems with the last step. I might have written ##\frac {dA_x} {dt}...
View full post »
Thread 'Griffith, Electrodynamics, 4th Edition, Example 4.8. (Second part)'

Thread 'Griffith, Electrodynamics, 4th Edition, Example 4.8. (Second part)'

I am reading the Griffith, Electrodynamics book, 4th edition, Example 4.8. I want to understand some issues more correctly. It's a little bit difficult to understand now. > Example 4.8. Suppose the entire region below the plane ##z=0## in Fig. 4.28 is filled with uniform linear dielectric material of susceptibility ##\chi_e##. Calculate the force on a point charge ##q## situated a distance ##d## above the origin. In the page 196, in the first paragraph, the author argues as follows ...
View full post »

Similar threads

I How to use geometrical symmetries -- general advice? (Vector potential)
Replies
2
Views
1K
I Conditions for applying Gauss' Law
Replies
1
Views
1K
I Maxwell's equations in the presence of matter -- Derivation
Replies
1
Views
1K
I How to calculate the ring resonator radii via Laplace?
Replies
0
Views
971
I Quadrupole moment tensor calculation for ellipsoid
Replies
3
Views
2K
I An attempt to understand the associated variable conventions in circuits
Replies
1
Views
2K
Question regarding eigenvectors
Replies
7
Views
2K
Engineering Why are the voltages calculated in this way? (CE BJT Amp circuit)
Replies
8
Views
2K
Calculating the force on an electron from two positive point charges
Replies
2
Views
1K
I Numerical calculations of a railgun yielded disappointing results
Replies
4
Views
1K

Hot Threads

Recent Insights

Back
Top