Oops, I stand corrected -- thanks, Frank. Once again I read too hastily.
A *mass*/spring combination mimics an inductor/capacitor, of course. A
damper adds resistance. So a spring/damper combination would act more
like an RC or RL circuit, but with a little stray L or C from the
spring's mass.

Hope I don't have to give up my new title. Titles really impress folks
in some parts of the world.

Roy Lewallen, W7EL, ROW, ASI, OFC

Frank wrote:

Of course, I should have mentioned a mass/spring/damper (equivalent to
capacitor/inductor/resistor), not just spring/damper. I think the only
physical system that can not be entirely modeled as an electrical analog is
a thermal system; which has no inductor equivalent.

Frank

"Roy Lewallen" wrote in message
...
Oops, I stand corrected -- thanks, Frank. Once again I read too hastily. A
*mass*/spring combination mimics an inductor/capacitor, of course. A
damper adds resistance. So a spring/damper combination would act more like
an RC or RL circuit, but with a little stray L or C from the spring's
mass.

Hope I don't have to give up my new title. Titles really impress folks in
some parts of the world.

Roy Lewallen, W7EL, ROW, ASI, OFC


No problem Roy. To be exact a mass is equivalent to a capacitor.
As in Newton's 2nd law: f = m*dv/dt, and its electrical analog
i = c*dv/dt, where "v" refers to velocity in the mechanical case,
and voltage in the electrical. I think this qualifies me to place the
letters "ASI" after my name. Well; I must admit I took a quick
look at my physical systems text book, so hope it does not
disqualify me.

Frank Meredith ASI

My EE students, noting that the characteristic equations are the same,
regularly convert mechanical problems (of the mass-spring-damper type) into
electrical problems, solve, and then convert back to mechanical answers.
Some ME students catch on and some just do not get it. Of course, it helps
if one is using SI units all round. I continue to be in awe of MEs who
always seem to know whether the "pounds" they are talking of are
sort-of-like mass, or sort-of-like force, or money. I have even had it
suggested that energy and power are sort-of the same thing.


I am keen on Roy being the collector of titles. I have quite enough for
a lifetime. 73 Mac N8TT etc.

--
J. Mc Laughlin; Michigan U.S.A.
Home:
"Roy Lewallen" wrote in message
...
Oops, I stand corrected -- thanks, Frank. Once again I read too hastily.
A *mass*/spring combination mimics an inductor/capacitor, of course. A
damper adds resistance. So a spring/damper combination would act more
like an RC or RL circuit, but with a little stray L or C from the
spring's mass.

Hope I don't have to give up my new title. Titles really impress folks
in some parts of the world.

Roy Lewallen, W7EL, ROW, ASI, OFC

Years ago I tracked down a constriction ("resistance") in my house's
water system with a bucket and stopwatch to measure flow ("current") and
a fuel pump pressure gauge to measure watter pressure ("voltage") and a
schematic of the "circuit". I kind of chuckled thinking of all the
simplified explanations of electricity using water -- I found it much
easier to convert in the other direction.

As for "pounds", I was always off by the acceleration of gravity squared
in the only two one-semester courses I took which weren't metric,
Statics and Dynamics. I never could remember which of those units --
pounds mass, pounds force, poundals, slugs, aargh, had the acceleration
already built in and which didn't. I finally managed by first converting
each problem to metric, solving it, then converting the result back to
that God-awful system of units.

Roy Lewallen, W7EL

J. Mc Laughlin wrote:
My EE students, noting that the characteristic equations are the same,
regularly convert mechanical problems (of the mass-spring-damper type) into
electrical problems, solve, and then convert back to mechanical answers.
Some ME students catch on and some just do not get it. Of course, it helps
if one is using SI units all round. I continue to be in awe of MEs who
always seem to know whether the "pounds" they are talking of are
sort-of-like mass, or sort-of-like force, or money. I have even had it
suggested that energy and power are sort-of the same thing.


I am keen on Roy being the collector of titles. I have quite enough for
a lifetime. 73 Mac N8TT etc.

Dear Roy:
I am in complete agreement. As an example, when dealing with antenna
tower evaluation I convert everything about the tower to SI (knowing the
approximate SI density of materials helps to ensure that the conversion was
done correctly), and then do the evaluation. When it comes to the design of
foundations, I need to convert the SI answer back into the other units so
that the skilled trades are able to do their thing.

How silly to have a system that depends on an assumed gravitational
system.

73 Mac N8TT

--
J. Mc Laughlin; Michigan U.S.A.
Home:
"Roy Lewallen" wrote in message
...
Years ago I tracked down a constriction ("resistance") in my house's
water system with a bucket and stopwatch to measure flow ("current") and
a fuel pump pressure gauge to measure water pressure ("voltage") and a
schematic of the "circuit". I kind of chuckled thinking of all the
simplified explanations of electricity using water -- I found it much
easier to convert in the other direction.

As for "pounds", I was always off by the acceleration of gravity squared
in the only two one-semester courses I took which weren't metric,
Statics and Dynamics. I never could remember which of those units --
pounds mass, pounds force, poundals, slugs, aargh, had the acceleration
already built in and which didn't. I finally managed by first converting
each problem to metric, solving it, then converting the result back to
that God-awful system of units.

Roy Lewallen, W7EL

Pound = Pound Weight, mass of one pound, acceleration (due to gravity)
of 32 ft/sec^2

Poundal = mass of one pound, acceleration of 1 ft/sec^2

(Cue Mrs.Nugatory to dive in with a 13-year-old's ridiculous
insistence on literal detail?)

Pound, Money = sort of like a dollar, but twice as valuable and more robust.

"J. Mc Laughlin" wrote in message
...
I continue to be in awe of MEs who
always seem to know whether the "pounds" they are talking of are
sort-of-like mass, or sort-of-like force, or money.

Actually $1.76 as of today, but used to be worth $2.40.
Any country too politically correct to call a terrorist a terrorist is not
long for the world.


Tis a real shame the spawn of a great people that endured so much with the
"stiff upper lip" are a bunch of wimps!

"Polymath" wrote in message
...

Pound, Money = sort of like a dollar, but twice as valuable and more
robust.

"Fred W4JLE" wrote:

: Actually $1.76 as of today, but used to be worth $2.40.
: Any country too politically correct to call a terrorist a terrorist is not
: long for the world.


So... in a NON-POLITICAL way please describe those people of the mid
to late 1700's who went around shooting soldiers who wore REDCOATS and
GOVERNED a land the that was at one stage part of the GREAT BRITISH
EMPIRE and had as one of its main cities BOSTON ?

On Wed, 13 Jul 2005 20:12:28 GMT,

(ZZZZPK ) wrote:

So... in a NON-POLITICAL way please describe those people of the mid
to late 1700's who went around shooting soldiers who wore REDCOATS and
GOVERNED a land the that was at one stage part of the GREAT BRITISH
EMPIRE and had as one of its main cities BOSTON ?

Hmmm,

The British Empire must, as one would expect, have an Emperor, and
particularly a British Emperor. If we scan the list of Royals over
time, certainly Britain had an Emperor (Carausius) during the Roman
era (hardly worth claiming as being British when you bend your knee to
Rome and that empire didn't even claim Wales).

Nearly as far back ago, there was a ship called Emperor.

There are a specie of penguins called Emperor.

Almost 100 years ago there was a George who went by Emperor and like
our own was numbered. But it wasn't George Trois, in fact it was
suggested that this George adopt the title "Emperor of the British and
Hanoverian Dominions," but he refused (and this suggestion only came
after 1802).

If we rummage around the list of Monarchs, then we find our recent
George, and Edward before him were "Emperors" and only of India. The
first "Emperor" was in fact an Empress (of that same named India).

So, by the question above, it must be discerned that in fact no one
ever took up arms against a GREAT BRITISH EMPIRE nor a MODEST BRITISH
EMPIRE nor even a PIDDLIN' BRITISH EMPIRE. So this usage of BRITISH
EMPIRE must in some sense mean the East India Trading Company (since
the only monarchs called Emperor/Empress are uniquely associated with
that sole state in our antipodes. The East India Trading Company held
property in Hudson Bay, so to put this presumed conflict into the
desired NON-POLITICAL way
Canadian (the people, not the political country) Consumers
revolting against a commercial entity - eh? What a bunch of hosers.

73's
Richard Clark, KB7QHC

Richard Clark wrote:

: The British Empire must, as one would expect, have an Emperor, and
: particularly a British Emperor. If we scan the list of Royals over
: time, certainly Britain had an Emperor (Carausius) during the Roman


i think ( 80% sure-ish) you'll find that
ONE of the lesser known titles of
HRH QE II is EMPEROR