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Re: vector products



Ludwik Kowalski wrote:

I second Larry's and Robert's plea for a little tutorial "for
the rest of us." ... Please assume that the reader is going
to be a student in the first semester of the first non-calculus
physics course. The student already knows kinematics, is
familiar with [the addition of] 3D vectors and Newton's laws.

Robert Cohen wrote:

It seems we can introduce the terminology of wedge
products at leasr when we deal with torque in physics
I, no? I think that at that point the bivector idea actually
fits better than the psuedovector idea. I'd like someone
with more knowledge of GA to explain how one might
go about discussing torque in a freshmen physics class. ...

Let me observe that the hypothetical student would be confused by this:

The fact is that the laws of electromagnetism are entirely
reflection-symmetric. ... In particular, the Maxwell
equations are commonly written using vector cross
products, which depend on the right-hand rule.

It is clear that JohnD is talking to an ideal physics teacher,
not to a student in the first semester of the first non-calculus
physics course. He wrote:

... A bivector is basically a patch of area, with a direction
of circulation marked on it. ... The bivector representing
the magnetic field of a long, straight wire2 is shown in
figure 3. ...

1) In other words a bivector is a scalar, not a vector. We
use a vector to represent a force but we use a bivector
to represent a torque. Is this correct?

2) Also E is a vector but B is not a vector. Right?

3) How would the magnetic flux be defined without
the idea that B is a vector ?

Ludwik Kowalski