xkcd: ?Physics Insight?
https://xkcd.com/3154/

?When Galileo dropped two weights from the Leaning Tower of Pisa, they
put him in the history books. But when I do it, I get 'detained by
security' for ?injuring several tourists.??

I have been to the top of the Leaning Tower of Pisa. It is quite a ways
up. Articles can achieve significant velocity from there.

Explained at:
https://www.explainxkcd.com/wiki/index.php/3154:_Physics_Insight

Lynn


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On Mon, 13 Oct 2025 17:22:10 -0500, Lynn McGuire
<lynnmcguire5@gmail.com> wrote:

xkcd: ?Physics Insight?
https://xkcd.com/3154/

?When Galileo dropped two weights from the Leaning Tower of Pisa, they

put him in the history books. But when I do it, I get 'detained by >security' for ?injuring several tourists.??

I have been to the top of the Leaning Tower of Pisa. It is quite a ways

up. Articles can achieve significant velocity from there.

IIRC, at some point Galileo was in charge of the Pisan artillery.

I wonder if he was trying to find out why their "time on target"
computations [1] never worked with Aristotle's view of how things
fell.

[1] The problem is getting guns of different calibers and other
characteristics affecting the path of the cannonballs to fire in the
correct order so that all of their cannonballs reach the target at the
same time. As time has marched on, of course, the "cannonballs" have
mutated into other forms, but the problem is the same.
--
"Here lies the Tuscan poet Aretino,
Who evil spoke of everyone but God,
Giving as his excuse, 'I never knew him.'"

--- PyGate Linux v1.0
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

In article <eqssekphm1g2ttdtq17kqqgo5krb90ub58@4ax.com>,
Paul S Person <psperson@old.netcom.invalid> wrote:

On Mon, 13 Oct 2025 17:22:10 -0500, Lynn McGuire
<lynnmcguire5@gmail.com> wrote:

xkcd: ?Physics Insight?
https://xkcd.com/3154/

?When Galileo dropped two weights from the Leaning Tower of Pisa, they
put him in the history books. But when I do it, I get 'detained by >security' for ?injuring several tourists.??

I have been to the top of the Leaning Tower of Pisa. It is quite a ways >up. Articles can achieve significant velocity from there.

IIRC, at some point Galileo was in charge of the Pisan artillery.

I wonder if he was trying to find out why their "time on target"
computations [1] never worked with Aristotle's view of how things
fell.

I have some doubts on whether that concept would occur to him. IIRC, the
whole idea of "Time on Target" was for explosive shells.

--
"We have advanced to new and surprising levels of bafflement."
Imperial Auditor Miles Vorkosigan describes progress in _Komarr_. ?-----------------------------------------------------
Robert Woodward robertaw@drizzle.com

--- PyGate Linux v1.0
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On 10/14/2025 12:09 PM, Robert Woodward wrote:

In article <eqssekphm1g2ttdtq17kqqgo5krb90ub58@4ax.com>,
Paul S Person <psperson@old.netcom.invalid> wrote:

On Mon, 13 Oct 2025 17:22:10 -0500, Lynn McGuire
<lynnmcguire5@gmail.com> wrote:

xkcd: ?Physics Insight?
https://xkcd.com/3154/

?When Galileo dropped two weights from the Leaning Tower of Pisa, they
put him in the history books. But when I do it, I get 'detained by
security' for ?injuring several tourists.??

I have been to the top of the Leaning Tower of Pisa. It is quite a ways >>> up. Articles can achieve significant velocity from there.

IIRC, at some point Galileo was in charge of the Pisan artillery.

I wonder if he was trying to find out why their "time on target"
computations [1] never worked with Aristotle's view of how things
fell.

I have some doubts on whether that concept would occur to him. IIRC, the whole idea of "Time on Target" was for explosive shells.

Were explosive shells used before the USA Civil War ?

Lynn


--- PyGate Linux v1.0
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

On 10/14/2025 4:26 PM, Lynn McGuire wrote:

On 10/14/2025 12:09 PM, Robert Woodward wrote:

In article <eqssekphm1g2ttdtq17kqqgo5krb90ub58@4ax.com>,
ÿ Paul S Person <psperson@old.netcom.invalid> wrote:

On Mon, 13 Oct 2025 17:22:10 -0500, Lynn McGuire
<lynnmcguire5@gmail.com> wrote:

xkcd: ?Physics Insight?
ÿÿÿ https://xkcd.com/3154/

?When Galileo dropped two weights from the Leaning Tower of Pisa, they >>>> put him in the history books.ÿ But when I do it, I get 'detained by
security' for ?injuring several tourists.??

I have been to the top of the Leaning Tower of Pisa.ÿ It is quite a
ways
up.ÿ Articles can achieve significant velocity from there.

IIRC, at some point Galileo was in charge of the Pisan artillery.

I wonder if he was trying to find out why their "time on target"
computations [1] never worked with Aristotle's view of how things
fell.

I have some doubts on whether that concept would occur to him. IIRC, the
whole idea of "Time on Target" was for explosive shells.

Were explosive shells used before the USA Civil War ?

Do you know the words to "The Star-Spangled Banner?"

(Earlier possibilities include 13th century China and 14th century Venice.)

--
Mark Jackson - https://mark-jackson.online/
Against the assault of laughter nothing can stand.
- Mark Twain

--- PyGate Linux v1.0
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

On 10/14/2025 3:57 PM, Mark Jackson wrote:

On 10/14/2025 4:26 PM, Lynn McGuire wrote:

On 10/14/2025 12:09 PM, Robert Woodward wrote:

In article <eqssekphm1g2ttdtq17kqqgo5krb90ub58@4ax.com>,
ÿ Paul S Person <psperson@old.netcom.invalid> wrote:

On Mon, 13 Oct 2025 17:22:10 -0500, Lynn McGuire
<lynnmcguire5@gmail.com> wrote:

xkcd: ?Physics Insight?
ÿÿÿ https://xkcd.com/3154/

?When Galileo dropped two weights from the Leaning Tower of Pisa, they >>>>> put him in the history books.ÿ But when I do it, I get 'detained by
security' for ?injuring several tourists.??

I have been to the top of the Leaning Tower of Pisa.ÿ It is quite a >>>>> ways
up.ÿ Articles can achieve significant velocity from there.

IIRC, at some point Galileo was in charge of the Pisan artillery.

I wonder if he was trying to find out why their "time on target"
computations [1] never worked with Aristotle's view of how things
fell.

I have some doubts on whether that concept would occur to him. IIRC, the >>> whole idea of "Time on Target" was for explosive shells.

Were explosive shells used before the USA Civil War ?

Do you know the words to "The Star-Spangled Banner?"

(Earlier possibilities include 13th century China and 14th century Venice.)

Ah ! Very true.

Lynn


--- PyGate Linux v1.0
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

Lynn McGuire wrote:

On 10/14/2025 3:57 PM, Mark Jackson wrote:

On 10/14/2025 4:26 PM, Lynn McGuire wrote:

On 10/14/2025 12:09 PM, Robert Woodward wrote:

In article <eqssekphm1g2ttdtq17kqqgo5krb90ub58@4ax.com>,
ÿ Paul S Person <psperson@old.netcom.invalid> wrote:

On Mon, 13 Oct 2025 17:22:10 -0500, Lynn McGuire
<lynnmcguire5@gmail.com> wrote:

xkcd: ?Physics Insight?
ÿÿÿ https://xkcd.com/3154/

?When Galileo dropped two weights from the Leaning Tower of Pisa, >>>>>> they
put him in the history books.ÿ But when I do it, I get 'detained by >>>>>> security' for ?injuring several tourists.??

I have been to the top of the Leaning Tower of Pisa.ÿ It is quite >>>>>> a ways
up.ÿ Articles can achieve significant velocity from there.

IIRC, at some point Galileo was in charge of the Pisan artillery.

I wonder if he was trying to find out why their "time on target"
computations [1] never worked with Aristotle's view of how things
fell.

I have some doubts on whether that concept would occur to him. IIRC,
the
whole idea of "Time on Target" was for explosive shells.

Were explosive shells used before the USA Civil War ?

Do you know the words to "The Star-Spangled Banner?"

(Earlier possibilities include 13th century China and 14th century
Venice.)

China,definitely, and I know of Venetian use in the 15th century.

Ah !ÿ Very true.

Those were Congreve rockets which he British were using with very mixed success at the time. When Wellington wanted to stress just how well a
certain battle had gone, he commented that event the Congreve rockets
had all flown in the direction of the enemy. Generally he was happy if
fifty percent of them headed in the enemy's general direction.

Most British (and American, and French ...) wooden warships did not
carry explosive ammunition. The exception, for the British, were
specifically designed "bomb ships", which generally carried one very
large cannon firing fused shells. Much to my surprise the British did
have five bomb vessels and a rocket ship (which fired the aforesaid
Congreve rockets).

That was a most unusual force but Cochrane was not one to stick to
tradition.

I definitely would not have wanted to be on a wooden ship which was
firing Congreve rockets. But it seems to have survived.

The bombs from the ships would have packed a bigger punch, but they
lacked the red glare. And they were also pretty ineffective against fortifications.


William Hyde



--- PyGate Linux v1.0
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

Paul S Person <psperson@old.netcom.invalid> wrote:

IIRC, at some point Galileo was in charge of the Pisan artillery.

I wonder if he was trying to find out why their "time on target"
computations [1] never worked with Aristotle's view of how things
fell.

_Two New Sciences_ has a discussion of this and is well worth
reading. Note that Galileo is thinking throughout of bodies
attracted to the earth and never makes that great jump of Newton's.
--scott


--
"C'est un Nagra. C'est suisse, et tres, tres precis."

--- PyGate Linux v1.0
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On 15/10/25 13:15, William Hyde wrote:
snip

I know of Venetian use in the 15th century.

How old are you, William Hyde?

MANY BLANK SPOILER LINES FOLLOW.
































:-)


--- PyGate Linux v1.0
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Scott Dorsey <kludge@panix.com> wrote:

Paul S Person <psperson@old.netcom.invalid> wrote:

IIRC, at some point Galileo was in charge of the Pisan artillery.

I wonder if he was trying to find out why their "time on target" >>computations [1] never worked with Aristotle's view of how things
fell.

_Two New Sciences_ has a discussion of this and is well worth
reading. Note that Galileo is thinking throughout of bodies
attracted to the earth and never makes that great jump of Newton's.

I take that back. I thought there was a discussion of time of flight
but looking it up I find there is not.... it would be difficult to do
without the calculus I suspect.
--scott


--
"C'est un Nagra. C'est suisse, et tres, tres precis."

--- PyGate Linux v1.0
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On Wed, 15 Oct 2025 10:34:04 -0400 (EDT), kludge@panix.com (Scott
Dorsey) wrote:

Scott Dorsey <kludge@panix.com> wrote:

Paul S Person <psperson@old.netcom.invalid> wrote:

IIRC, at some point Galileo was in charge of the Pisan artillery.

I wonder if he was trying to find out why their "time on target" >>>computations [1] never worked with Aristotle's view of how things
fell.

_Two New Sciences_ has a discussion of this and is well worth
reading. Note that Galileo is thinking throughout of bodies
attracted to the earth and never makes that great jump of Newton's.

How ... Aristotelian of him.

Did he rule out other "worlds" (solar systems if not universes [1])
because their matter would to attracted to the center of our Earth?

[1] The last section of the translation of Newton's /Principia/ in the collection called /The Great Books of the Western World/ is called
"The System of the World". It is about the solar system. IIRC, it is
here that he suggests solar gravity is the force posited by Kepler
that keeps the planets moving in elliptical orbits. So in Newton's
day, "the world" was at least the solar system; in Aristotle's it
probably included the fixed sphere of stars as well -- that is, was
what we call the Universe. It would be interesting to know if Bruno,
when he contended that other worlds existed, was talking about Mars or
about other universes.

I take that back. I thought there was a discussion of time of flight
but looking it up I find there is not.... it would be difficult to do >without the calculus I suspect.

I appear to be projecting much more modern concepts of artillery onto
the distant past.

Ancient geometry did include conic sections, although whether they
were related to the path of missiles used in indirect fire [1] I do
not know.

[1] Direct fire is when you shoot straight at the target. Indirect
fire is when you shoot up into the air and the missile falls down from
on high. The ancients, of course, had several forms of missiles
capable of indirect fire: arrows, perhaps some types of spears,
pebbles (slingers), and probably others as well. The large rocks
propelled by various seige engines were generally used in indirect
fire, it being hard to get them to fly level for any great distance.
--
"Here lies the Tuscan poet Aretino,
Who evil spoke of everyone but God,
Giving as his excuse, 'I never knew him.'"

--- PyGate Linux v1.0
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

On 10/15/2025 10:34 AM, Scott Dorsey wrote:

Scott Dorsey <kludge@panix.com> wrote:

Paul S Person <psperson@old.netcom.invalid> wrote:

IIRC, at some point Galileo was in charge of the Pisan
artillery.

I wonder if he was trying to find out why their "time on target"
computations [1] never worked with Aristotle's view of how
things fell.

_Two New Sciences_ has a discussion of this and is well worth
reading. Note that Galileo is thinking throughout of bodies
attracted to the earth and never makes that great jump of
Newton's.

I take that back. I thought there was a discussion of time of
flight but looking it up I find there is not.... it would be
difficult to do without the calculus I suspect.

Probably not. Did they know the muzzle velocity of the devices to which
a given distance/angle table applies? Then, assuming no meaningful
impact of air resistance:

time-to-target = distance divided by (muzzle velocity)*cos(angle).

--
Mark Jackson - https://mark-jackson.online/
Against the assault of laughter nothing can stand.
- Mark Twain

--- PyGate Linux v1.0
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

Mark Jackson wrote:

On 10/15/2025 10:34 AM, Scott Dorsey wrote:

Scott Dorsey <kludge@panix.com> wrote:

Paul S Personÿ <psperson@old.netcom.invalid> wrote:

IIRC, at some point Galileo was in charge of the Pisan
artillery.

I wonder if he was trying to find out why their "time on target"
computations [1] never worked with Aristotle's view of how
things fell.

_Two New Sciences_ has a discussion of this and is well worth
reading.ÿ Note that Galileo is thinking throughout of bodies
attracted to the earth and never makes that great jump of
Newton's.

I take that back.ÿ I thought there was a discussion of time of
flight but looking it up I find there is not.... it would be
difficult to do without the calculus I suspect.

Probably not.ÿ Did they know the muzzle velocity of the devices to which
a given distance/angle table applies?ÿ Then, assuming no meaningful
impact of air resistance:

time-to-target = distance divided by (muzzle velocity)*cos(angle).

I seem to recall from Aubrey that one of Elizabeth's scholars applied mathematics to gunnery, possibly Dr Dee before he became an occultist.

The Parliamentary officer Nathaniel Nye directed cannon in the English
civil war and published a book on the mathematics of it in 1647, in
which he cited a much earlier Italian mathematician, Tartaliga, who
wrote on the subject in 1537.

William Hyde

--- PyGate Linux v1.0
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Paul S Person <psperson@old.netcom.invalid> wrote:

I appear to be projecting much more modern concepts of artillery onto
the distant past.

Ancient geometry did include conic sections, although whether they
were related to the path of missiles used in indirect fire [1] I do
not know.=20

I don't know, but Galileo does talk about how the projectile follows a
parabola and why. He does mention indrect fire although I don't think
it is very useful unless you have good spotting, which would have been
a problem at the time.

But time of arrival is more difficult since the projectile velocity
isn't constant at every point along that parabola. Vectors and the
calculus make these simple problems but they would be difficult to
solve without them.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

--- PyGate Linux v1.0
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