List of all the cross and dot products in physics?

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Discussion Overview

The discussion revolves around identifying and compiling a list of physical quantities that involve cross and dot products, with a focus on their applications in various fields such as electromagnetism and fluid dynamics. Participants seek to expand on known examples and explore additional contexts where these mathematical operations are utilized.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant lists known examples of cross products: Lorentz force, angular momentum, and torque, and seeks to add more to the list.
  • Another participant describes the geometric interpretation of dot products as projections and mentions their use in calculating work done through force and displacement.
  • Further examples of dot products and cross products in electromagnetism are provided, including the force equation in EM theory and the Poynting vector.
  • A participant expresses skepticism about the existence of unique examples of cross and dot products in special relativity (SR), suggesting that the previous reply was overly detailed.
  • Another participant suggests including the del operator, specifically gradient, divergence, and curl, as additional contexts for cross and dot products.

Areas of Agreement / Disagreement

Participants generally agree on the importance of cross and dot products in physics but have differing views on the uniqueness of examples in special relativity and the completeness of the initial list provided.

Contextual Notes

Some assumptions about the definitions and contexts of cross and dot products may not be fully articulated, and the discussion does not resolve the completeness of the examples provided.

Epix Trix
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the calculation of many quantities involve cross and dot products in their formulae.

For cross products, i only know of three: lorentz force, angular momenta and torque.
For dot products, i only know of one: work done

im hoping to add more to my list. Can you guys help me include other commonly used formulae which also involve cross and dot products?
 
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dot products have a geometric description as the projection of one vector on another

and similarly for cross product where you get the perpendicular projection of one vector on another.

EM theory uses vector cross product for direction of magnetism relative to current flowing through a wire and vice versa.

(force dot dr) as a differential for work (ie integrate over it to get the work done)

p v dot dS for fluid flow out of a surface differential where p is the fluid density and v is the velocity

EM theory f = q (E + v x B)

EM theory the poynting vector P = E x H

and energy density of the EM field W = 1/2 (E dot D + H dot B )

Relativity may have other examples as well.
 
i don't think there are any unique examples of cross and dot products in SR

but thanks for the lengthy reply
 
you could extend your search to include the del operator ie the gradient, the divergence and the curl.
 

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