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Re: Units of electricity

Original poster: "Chris Rutherford" <chrismrutherford@xxxxxxxxxxxxxx>

Hi Jared,

Didn't Tesla himself use the old mechanical analogies for tuned circuit, i.e. likening them to a mass on spring with friction, referring to things like impedance as inertia, or am i mistaken here? I have often noted the similarities between mechanical and electrical systems. Take for example the energy stored in a capacitor E=1/2CV^2 (c=capacitance, v=voltage) and then look at the energy in a moving object E=1/2MV^2 (m=mass, v=velocity). I agree with you, but it would be nice to see these things worked out from first principles.


Chris R

On 8/24/06, Tesla list <<mailto:tesla@xxxxxxxxxx>tesla@xxxxxxxxxx> wrote:
Original poster: Skip Malley <<mailto:skip@xxxxxxxxxxxxxxx>skip@xxxxxxxxxxxxxxx>

This is one of the most confusing explanations of these thoughts as I
have ever seen.  It has just added confusion for many instead of
relieving it.  I did very well in high school and college physics,
but still have a bunch of ????????????? after reading this email.

To relate any of these basic formulas, it is necessary to define each
term of these equations or formulas.

Let me give a few examples:

F = MA (always)
F  force (Newtons)
M  mass (Kg))
A  acceleration  (Meters per Second *2)

Q  charge (Qulombs)
C  capacitance (Farads)
V  (Volts)

I could define more...

Please don't just give a bulk of formulas if you do not define the
parts and pieces thereof.

Please repeat this email with the necessary information added.


At 08:59 AM 8/23/2006, you wrote:
>Original poster: Jared E Dwarshuis <<mailto:jdwarshui@xxxxxxxxx>jdwarshui@xxxxxxxxx>
>The mechanical units of electricity:
>I have often pondered why there are so many close analogies between
>the mechanical world and the electrical world. Certainly it is true
>that force was pivotal in defining electricity, but there is an
>overall pattern that emerges in the intrinsic properties.
>We start by playing a simple algebra game with the fundamental unit of
>charge "q"
>We multiply meters by both the numerator and denominator and write:
>q = m ( As/m )
>I = m/s ( As/m )
>d(I)/dt = m/(ss) ( As/m )
>Whenever we encounter a unit of electricity and see Amp's. We must
>group it to satisfy:
>  ( As/m)     Also known as: (Coulombs per meter)
>Thus Voltage with the units of: kg mm 1/sss 1/A gets written as: kg m/
>ss   (m/As)
>  Or simply:
>Voltage = Force (m/As)
>E = kg/ss (m/As)
>Resistance = kg/s (m/As)sqrd
>Capacitance = ss/kg (As/m)sqrd
>Permittivity = ss/ m kg (As/m)sqrd
>Magnetic flux = kg m/s (m/As)
>B = kg/ms (m/As)
>L = kg (m/As)sqrd
>Permeability = kg/m (m/As)sqrd
>Force = Mass x Acceleration  and Voltage = L dI/dt  are now equivalent
>Force = kx and q = CV are now equivalent
>Newton's second law and Lenz law are now equivalent
>The expressions for impedance are now equivalent to the mechanical
>u e = density/force = ss/mm
>Esqrd e = Bsqrd /u = density times velocity squared = pressure
>(incompressible fluid flow)
>I hope this will aid people in conceptually understanding electricity
>a little bit better.
>Sincerely Jared Dwarshuis
>August 23, 2006