Re: COLLISION 2

[Leigh Palmer <palmer@SFU.CA>]

> What can have heated the spring 'very hot'?
> Did we not work an example case of a spring as heavily loaded as it
> could be - yet the temperature rise in degrees could be counted on
> the fingers of one hand? David was postulating only one compression
> stroke or one compression and one relaxation stroke, respectively.

I guess my calculation was misunderstood. What it showed was that the
maximum tensile elastic energy storage possible in a steel spring has
a thermal equivalent which amounts to a rise in temperature of the
same mass by less than a degree. I certainly did not intend that the
process be considered as one which would raise the temperature of the
steel by that much; it will not do so! The temperature rise (if there
is any) will be very much smaller than that.

I was going to stay out of this (hah!) but as long as I have my oar
in, let me stir it a bit more. When Joule was twirling his oar he was
increasing the entropy of the water. It is true that he was not
heating the water. Change in entropy is not associated with an actual
process; it is associated with *any* hypothetical reversible process
capable of taking an identical system from the same initial to the
same final state as the system in question. All such processes will
yield the same path integrals of dQ/T, and the meaning of dQ is well
defined for the hypothetical process.

Somehow that discussion got so far off track that it was irreparable.

Leigh