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Re: There's work, and then there's work



David Rutherford wrote:

The water flowing out through the side hole is analogous to the
particles in the environment outside the wire that have picked up energy
from the particles inside the wire. The particles inside the wire have
transferred the part of their energy that's due to the transverse
component of their motion to the particles outside the wire. Therefore,
the calorimeter experiment measures _only_ the part of the energy of the
particles inside the wire that is due to the _transverse_ component of
their velocity. Similarly, the current experiment measures _only_ the
part of the energy of the particles inside the wire that is due to the
_longitudinal_ component of their velocity. The reason that the two
experiments come out with the same result is that, on average, the
transverse and longitudinal components of the velocity are equal.


The two experiments you refer to are actually one and the same. The purpose of
measuring the current through the resistor is so one can CALCULATE i^2 * R,
integrate it over time, and PREDICT the result of the calorimetry experiment. OTOH,
you can actually PERFORM the calorimetry experiment. One of these is theoretical,
the other is a measured result - which is why they give the same value. You are
attempting to count the same result twice.

Bob at PC