Basic electrical concepts question

in article snipped-for-privacy@4ax.com, dave y. at snipped-for-privacy@ameritech.net wrote on 1/2/04 9:59 AM:

There are many equivalent concepts. You can develop all of mechanics from Newton's second law. That includes the conservation of energy in mechanical systems. As a byproduct, classical thermodynamics can be derived from f=ma.

So, if you have two theories that are EQUIVALENT, one form is not fundamentally better than the other.

Bill

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Repeating Rifle
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Regarding energy and force

When dealing in the mechanical engineering world, force is able to be used in only one of the three time-areas of failure prediction/capacity. ( And the same applies when dealing in the micro/small macro areas of electrical engineering)

Note that energy is used to derive the force equations (most advanced engineering texts will have the derivations).

First area: Force is used when the energy can distribute rapidly within a part relative to input. (weight on a beam, dynamic input, etc.)

Third area: Energy density is used when the energy is not able to distribute rapidly relative to input, but is in "waves" (shock input, explosives, etc.)

Note -the classic illustraion to demonstrate the phenomona is to input bending energy into the plane of a six-sided star - when the energy can rapidly distribute, the star breaks across the narrow section between corners at the bases of opposite points, the shortest dimension. When the same amount of energy is entered into the same star very rapidly, the star breaks from point tip to opposite point tip - the longest dimension.

Second area: That is when the energy input is near the natural frequency of the part, and it is governed by the vibration equations, either in force or in energy density.

but note that the force equations there are also derived from energy equations, not the other way around.

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Hobdbcgv

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