Re: How far does an object fall during the first half second after it's released?
From: Gene Nygaard (gnygaard_at_nccray.com)
Date: 07/04/04
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Date: Sun, 04 Jul 2004 10:57:48 -0500
On 3 Jul 2004 20:38:53 -0700, pcardinale@volcanomail.com (Paul
Cardinale) wrote:
>"Richard Henry" <rphenry@home.com> wrote in message news:<1JDFc.8784$151.3742@fed1read02>...
>> "Gene Nygaard" <gnygaard@nccray.com> wrote in message
>> news:glbde0lmfdnu3o0g0mmmh6hhjje6od8o2h@4ax.com...
>> > On Sat, 3 Jul 2004 05:55:52 -0700, "Richard Henry" <rphenry@home.com>
>> > wrote:
>> >
>> > >
>> > >"Gene Nygaard" <gnygaard@nccray.com> wrote in message
>> > >news:d7vce0dhbjt45oopeo0b689n1chb13ptfd@4ax.com...
>> > >> On Fri, 2 Jul 2004 15:32:00 -0700, "Richard Henry" <rphenry@home.com>
>> > >> wrote:
>> > >>
>> > >> >
>> > >> >"Gene Nygaard" <gnygaard@nccray.com> wrote in message
>> > >> >news:g39be01bfq6v1nli0bf1d0a857l8t4fc1r@4ax.com...
>> > >> >> On Fri, 02 Jul 2004 13:02:21 GMT, Sam Wormley <swormley1@mchsi.com>
>> > >> >> wrote:
>> > >> >>
>> > >> >> >"Donald G. Shead" wrote:
>> > >> >> >>
>> > >> >> >> "Richard Henry" <rphenry@home.com> wrote in message
>> news:<HTZEc.6180$151.4316@fed1read02>...
>> > >> >> >> > "Donald G. Shead" <dcshead@charter.net> wrote
>> Cut<
>> > >> >> >> > >
>> > >> >> >> > > Virtually all good weight-scales, _if set to zero when
>> empty_;
>> in
>> the
>> > >> >> >> > > controled environment of a laboratory: Whether at the equator
>> or
>> the
>> > >> >> >> > > poles will register the same weight for any item!
>> > >> >> >> >
>> > >> >> >> > No they don't.
>> > >> >> >>
>> > >> >> >> Will you please tell me why they don't.
>> > >> >> >
>> > >> >> > w = mg
>> > >> >> >
>> > >> >> > g has different values at different altitudes and different
>> locations
>> > >> >> > on the Earth at the same altitude. This is a problem for spring
>> scales.
>> > >> >>
>> > >> >> Big deal. You are adding additional specifications, narrowly
>> > >> >> restricting the type of scales you are talking about.
>> > >> >>
>> > >> >> So "No, they don't" should not be changed to "Yes, they do" but
>> rather
>> > >> >> to "Sometimes they do, and sometimes they don't."
>> > >> >
>> > >> >Really? With which of these statements do you disagree:
>> > >> >
>> > >> >1. The original statement described "weight-scales".
>> > >> >
>> > >> >2. Weight = mass times g, the local gravitational acceleration.
>> > >> >
>> > >> >3. g varies over the surface of the Earth, especially at "the equator
>> or
>> > >> >the poles", as in the original statement.
>> > >> >
>> > >> >4. Weight varies over the surface of the Earth, especially at "the
>> equator
>> > >> >or the poles", as in the original statement.
>> > >>
>> > >> 2 and 4, of course.
>> > >Ah. The New Physics. What is the p[roper relationship of weight and
>> mass,
>> > >then, when the speaker is making references to variations (or lack
>> thereof)
>> > >over the surface of the earth?
>> >
>> > Depends on which meaning of each of those ambiguous words is intended.
>> >
>> > 1. The atomic weight of helium does not vary over the surface of the
>> > earth. Similarly for molecular weight or formula weight.
>> >
>> > 2. The troy weight of a bar of platinum does not vary oer the surface
>> > of the earth.
>> >
>> > 3. The carat weight of a diamond doesn't vary over the surface of the
>> > earth.
>> >
>> > 4. The net weight of a box of cereal does not vary over the surface
>> > of the earth, not does the tare weight of the packaging.
>> >
>> > 5. My body weight does not vary over the surface of the earth, if I
>> > am using the definition of weight normal for medicine or sports, the
>> > reasons we usually weigh ourselves. Just because some fools writing
>> > physics textbooks or designing science museum exhibits use a
>> > nonstandard meaning of the word "weight" in this context doesn't
>> > change the fact that the kilograms used throughout the world
>> > (including many hospitals in the U.S.A.) for this weight are the
>> > proper SI unitf for the purpose.
>> >
>> > So, what the hell do you think that the "proper relationship between
>> > weight and mass" is in cases 1 through 5 above? Since I'm "making
>> > reference to variations over the surface of the earth" and since the
>> > weight in these instances does not vary, does that mean that you'd
>> > think that there is some other quantity called "mass" which does vary
>> > in these cases?
>> >
>> > >To complicate matters, I bought a yard chain for the new dog yesterday.
>> > >Printed on the package was the statement "Breaking strength over 515
>> > >kilograms".
>> >
>> > That's not really a complication to this particular discussion--that
>> > quantity is not called "weight" in anybody's book. (Fishing line is a
>> > different story, however.)
>> >
>> > But what about my ketchup bottle: "Net wt. 24 oz (1 lb 8 oz) 680 g"?
>> > What are those grams? What are those pounds and ounces?
>> >
>> > Don't you pay any attention whatsoever to the world around you? Why
>> > do you put your blinders on when you run across examples like this, or
>> > my examples above?
>> >
>> > Certainly we do still see many vestiges of the use of the
>> > once-legitimate kilograms force. But when kilograms are used for
>> > something that is called "weight," the overwhelming majority of the
>> > time these are the units legitimate in the modern metric system, the
>> > International System of Units. They are units of mass. They are not
>> > kilograms force.
>>
>> You have given many fine examples and a logical arguemnt. Unfortunately, it
>> has very little to do with Mr. Shead's original statement.
>
>Nygaard is incapable of grasping what 'weight' means in the context of physics.
>
>Paul Cardinale
So, what Dense Donny Shead talks about is "in the context of physics."
Good grief! How silly can you get? He knows little about physics,
and much of what he does "know" is wrong.
Shead is a crackpot who routinely posts everything he writes to two
newsgroups he never follows himself: sci.physics and sci.math. Does
that also mean that everything Shead posts is "in the context of
mathematics" as well? He knows even less about mathematics than he
does about physics, being tripped up by the simplest algebra.
Can you tell me what, exactly, does "weight" mean when Shead talks
about weight? Is it always the same thing? What are those
"weight-scales" he was talking about--weren't you paying attention any
of the many times when he has described his understanding of the
operation of balances in that connection?
So what, exactly, do you mean by "in the context of physics"? Forget
about Shead, and put some reasonable limits on what in included of the
scope of the boundaries of this area in which you claim I "am
incapable of grasping the meaning of 'weight'"
Please explain in detail, considering the following:
1. A physicist talks about the atomic weight of an element. Do you
remember when this was different in physics than it was in chemistry?
It was when I first learned this, or at least we were still using
textbooks that distinguished them. One was based on the naturally
occuring mix of oxygen atoms being 16 exactly, the other on oxygen 16
being 16. Is that "in the context of physics"? Here's Eric
Weisstein, on his World of Physics web site,
http://scienceworld.wolfram.com/physics/AtomicWeight.html
Atomic Weight
The average mass of the naturally occurring isotopes of an
element, based on abundance and using the C = exactly 12 scale.
http://scienceworld.wolfram.com/biography/Berzelius.html
Berzelius, Jöns (1779-1848)
...
In his weights, he used oxygen as a standard, setting its weight equal
to exactly 100.
http://scienceworld.wolfram.com/biography/Stas.html
Stas, Jean (1813-1891)
Belgian chemist who determined atomic weights more accurately than
had been done before. He used oxygen as a reference weight, taking it
to have an atomic weight of exactly 16.
Aren't the preceding examples "in the context of physics"?
2a. A hunter uses the weight of a bullet and its speed to calculate
its kinetic energy. Is that "in the context of physics"?
2b. A scientist who is a forensic ballistics expert uses the weight
and speed of a bullet to calculate its kinetic energy. Is that "in
the context of physics"?
2c. Some unknown newbie on alt.sci.physics asks about using the
weight and speed of a bullet to calculate its kinetic energy. Is that
"in the context of physics"?
3. A physics teacher talks about the weight of a box of cheese. Just
because this takes place in a physics classroom, that doesn't change
the rules governing that sale of cheese, does it?
4. NASA tells us that the weight of the Apollo 11 Lunar Module at
liftoff of its ascent stage was 10,776.6 lb. Is that "in the context
of physics"? What would this "weight" be, if it were expressed in
units of force?
5. Is this "in the context of physics" because it appears on a web
site dedicated to physics?
http://scienceworld.wolfram.com/physics/Bag.html
A unit of weight equal to 94 pounds.
This particular bag is the one used for portland cement, equal to 94
lb (42.6 kg). Is this "in the context of physics"? Weisstein
apparently thinks so. But this "unit of weight" is not a "unit of
force."
What about the several following items from the same web site?
6. http://scienceworld.wolfram.com/physics/Pennyweight.html
Pennyweight
A unit of mass used to measure precious metals and defined so
that there are 24 grains in 1 pwt. One pennyweight is equal to 1.555 g
7. http://scienceworld.wolfram.com/biography/Helmont.html
Helmont, Jan van (1580-1644)
Van Helmont performed a famous experiment in which he grew a willow
tree in a carefully weighed amount of soil. He noticed that little of
the soil was consumed, but that the weight of the tree greatly
increased. He concluded that the extra weight came from the water.
8. http://scienceworld.wolfram.com/biography/Black.html
Black, Joseph (1728-1799)
He showed for the first time that reactions involving airs conserved
weight. In his experiments, Black made consistent use of quantitative
weight measurements.
9. http://scienceworld.wolfram.com/physics/AvogadrosHypothesis.html
By comparing the masses of equal volumes of different gases at
identical temperatures and pressures, the weight ratios of the gas
molecules could be measured.
10.
http://scienceworld.wolfram.com/physics/SynthesisImagingArray.html
The weight of an antenna is 193,000 kg.
11. http://scienceworld.wolfram.com/physics/Apounce.html
A unit of mass in the Apothecaries' system of weights
12.
http://www.transcat.com/TechReference/PDFs/FormulasConversions/Conversions.pdf
Heat of melting or heat of fusion, L, is the quantity of heat needed
to melt one unit weight of substance without changing its temperature,
or H = M x L.
13. Here are some more space examples. Are these "in the context of
physics"?
http://www.theandyzone.com/launchzone/sweight.htm
Shuttle Weight Reductions
Hardware Modified
Lightweight crew seats (189 lbs.)
http://www.marsinstitute.info/rd/faculty/dportree/rtr/rs39.html
Mars arrival: . . .
Weight at touchdown is 4477 kilograms.
14. http://www.engineeringtoolbox.com/8_239.html
Enthalpy is the measure of the total energy in the air, the energy
content per unit air weight (Btu/lb_da) (dry air).
15. http://www.metalwebnews.com/howto/furnace2/furnace.html
Total Btu content of the metal = Weight x Btu / pound
Total Btu = 50 pounds x 498 Btu / pound = 24,900 Btu
16.
http://www.tempco.com/Engineering/heat_requirement_calculations.htm
Wattage required to heat material:
Weight of material (lbs) x Specific Heat (Btu/lb °F) x Temperature
rise (°F)
3.412 btu/watt hr. x Heat-up time (hr.)
17. A physicist buys a box of strawberries with a "Net weight: 1 lb
(454 g)" on the label, and passes them out to her colleagues in the
lab. Is that "in the context of physics."
18. Here are some more rocket scientists at work. Is this "in
physics"? Note that this is, of course, using the same definition of
weight that NASA used when they told us that the weight of the Apollo
11 Lunar Module at liftoff was 10,776.6 lb.
http://www.space.com/missionlaunches/mars_express_030530.html
Beagle 2 will be ejected from the Mars Express orbiter and fall onto
the martian surface following parachute braking and inflation of
gas-filled landing bags. The craft's landing weight is a mere
66-pounds (30-kilograms).
Exactly which of those examples are "in the context of physics," as
you use that term, and why or why not for each? In each of these
examples, would the "weight" be measured in units of force? Or in
units of mass?
How does your "grasp" of the meaning of the word "weight" differ from
mine, in each of the examples above?
-- Gene Nygaard http://ourworld.compuserve.com/homepages/Gene_Nygaard/ "It's not the things you don't know what gets you into trouble. "It's the things you do know that just ain't so." Will Rogers
- Next message: Uncle Al: "Re: Non singular Begining"
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- In reply to: Paul Cardinale: "Re: How far does an object fall during the first half second after it's released?"
- Next in thread: Gene Nygaard: "Re: How far does an object fall during the first half second after it's released?"
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