[geocentrism] Re: Weights and measures
- From: "Dr. Neville Jones" <ntj005@xxxxxxxxxxx>
- To: geocentrism@xxxxxxxxxxxxx
- Date: Mon, 28 May 2007 00:36:28 +0100 (BST)
Philip,
I do not know what is going on with posts and spam filters at the moment, but
some postings are certainly going awry.
The "triple equals" sign is (presuming you mean three lines one above the
other) "equivalent to" or "is defined as".
Neville.
philip madsen <pma15027@xxxxxxxxxxxxxx> wrote:
 Sorry everyone, but I only got about 3 posts from a dozen listed
on the archives.
Neville I found your amended latter post up there which explained the lbs, wt
lbs mass confusion and the need for, a = 32.. Thanks. Re the example..
errors are mine..
The original concerned a bullet of given weight and exit velocity, from which
Ke was to be calculated, (website) and yes twas in my old books units.. Lots
of old fuddies like me out there with web pages. I cant cut and paste from my
book, mores the pity..
However, after reading this article below I now know that the real unit of
weight is the poundal, .....Its enough to make me get serious with the new
units, especially when we got to "slugs".
But we are sposed to buy our butter by weight.. not mass... Who sells
butter by the Newton? Is that a new ton? lol. So if I want a pound of butter,
I should ask for 4.448222 Newtons please....But todays substitute pound of
butter is 500grms Mass, which according to below might be 5 newtons here on
Earth, if I knew what the s stood for in this:-
1 N � 1 kg·m/s²
And whats the triple equals sign?????
Philip.
PS for all our cleverness, why hasn't our keyboard included simple math
notation?
The poundal is a non-SI unit of force. It is a part of the absolute
foot-pound-second system of units, a coherent subsystem of English units
introduced in 1879, and one of several specialized subsystems of mechanical
units used as aids in calculations. It is defined as 1 lb·ft·s-2, or in
words, as the force necessary to accelerate a pound of mass at 1 foot per
second, per second. 1 pdl = 0.138 254 954 376 newton (N) exactly.
English units require re-scaling of either force or mass to eliminate a
numerical proportionality constant in the equation F = ma. The poundal
represents one choice, which is to rescale units of force. Since a pound of
force accelerates a pound of mass at about 32 ft/s2 (the acceleration of
gravity, g), the smaller unit of force represented by the poundal is chosen as
that force which accelerates a 1 pound mass at 1 foot per second squared. The
poundal is only about 1â??32 of a pound of force.
For example, a force of 1200 poundals is required to accelerate a man with
150 pounds mass at 8 feet per second squared, that is
. The poundal-force, pound-mass system is contrasted with an alternate
system in which pounds are used as force, and instead, the mass unit is
rescaled by a factor of 32. If force is given in pounds rather than poundals,
then an acceleration of one foot per second squared is induced in a mass of
about 32 pounds mass, for each applied pound of force. The mass unit of about
32 mass-pounds (32.2 to three digits) in this alternate system, is called a
slug. In this system, the above result would be expressed as
. Note that slugs and poundals are never used in the same system, since
each exists to solve the same problem, so that both should not be used together.
Rather than changing either force or mass units, one may choose to express
acceleration in units of the acceleration due to Earth's gravity. With this
system, the above result would be expressed as
. Units of force Newton
(SI unit) Dyne Kilogram-force
(Kilopond) Pound-force Poundal 1 N â?¡ 1 kg·m/s² = 105 dyn â??
0.10197 kp â?? 0.22481 lbf â?? 7.2330 pdl 1 dyn = 10â??5 N â?¡ 1
g·cm/s² â?? 1.0197Ã?10â??6 kp â?? 2.2481Ã?10â??6 lbf â?? 7.2330Ã?10â??5
pdl 1 kp = 9.80665 N = 980665 dyn â?¡ gn·(1 kg) â?? 2.2046 lbf â??
70.932 pdl 1 lbf â?? 4.448222 N â?? 444822 dyn â?? 0.45359 kp â?¡ gn·(1
lb) â?? 32.174 pdl 1 pdl â?? 0.138255 N â?? 13825 dyn â?? 0.014098 kp
â?? 0.031081 lbf â?¡ 1 lb·ft/s² The value of gn as used in the official
definition of the kilogram-force is used here for all gravitational units.
Retrieved from "http://en.wikipedia.org/wiki/Poundal"
Categories: Units of force | Imperial units | Customary units in the United
States
----- Original Message -----
From: Dr. Neville Jones
To: geocentrism@xxxxxxxxxxxxx
Sent: Sunday, May 27, 2007 11:46 PM
Subject: [geocentrism] E = mc^2
Now I have your attention.
Check the e-mail bulk message folders that your spam filters are adding to.
Do any of you have certain forum postings going into them?
Neville.
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Other related posts:
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- [geocentrism] Re: Weights and measures
- From: philip madsen
- [geocentrism] Re: E = mc^2
- From: philip madsen