Point charges in a regular hexagon

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SUMMARY

The correct formula for the force between point charges arranged in a regular hexagon is given by (2×sqrt3×k×q^2)/a^2. The variable 'a' represents the side length of the hexagon, while 'R' is the distance from an outer charge to the center. The calculation of 'R' as (sqrt3 × a)/2 is incorrect. Analyzing the x and y components of the forces acting on the center charge, along with symmetry, simplifies the solution significantly.

PREREQUISITES
  • Understanding of electrostatic forces and Coulomb's law
  • Familiarity with geometric properties of regular hexagons
  • Knowledge of vector components in physics
  • Basic algebra for manipulating equations
NEXT STEPS
  • Study the derivation of Coulomb's law in electrostatics
  • Learn about vector decomposition in two dimensions
  • Explore symmetry in physics problems involving multiple charges
  • Investigate the properties of regular polygons and their applications in physics
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Students and professionals in physics, particularly those focusing on electrostatics, as well as educators teaching concepts related to forces and geometry in a hexagonal arrangement.

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Homework Statement
Regular hexagon with side length a, has q,q,q,q,-q,-q point charges in vertices. What force would point charge q expierence if it was put in a hexagon center?
Relevant Equations
F=(kq^2)/R^2
R=(sqrt3 × a)/2
The answer should be (2×sqrt3×k×q^2)/a^2. What did I do wrong?
 

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I can't follow your working but...

Is 'a' the hexagon's side-length? Is 'R' the distance from an outer charge to the centre? If so, 'R=(sqrt3 × a)/2' is wrong!

Also, have you thought about the x and y components of each of the 6 forces on the centre charge? Then, using symmetry, the solution becomes very simple.

Edit - typo' corrected.
 
Last edited:
Steve4Physics said:
I can't follow your working but...

Is 'a' the hexagon's side-length? Is 'R' the distance from an outer charge to the centre? If so, 'R=(sqrt3 × a)/2' is wrong!

Also, have you thought about the x and y components of each of the 6 forces on the centre charge? Then, using symmetry, the solution becomes very simple.

Edit - typo' corrected.
Oh yeah, I mixed it up with inscribed circle radius, thanks.
 
The book claims the answer is that all the magnitudes are the same because "the gravitational force on the penguin is the same". I'm having trouble understanding this. I thought the buoyant force was equal to the weight of the fluid displaced. Weight depends on mass which depends on density. Therefore, due to the differing densities the buoyant force will be different in each case? Is this incorrect?

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