Instantaneous speed of gravity

[Rama]

Stationary helicopter in air. Neo hanging in air with 1 km long rope.
One end of rope attached to helicopter and other end in hands of neo.
Suppose speed of compression waves in rope is 100 m/s. If rope at
helicopter end is cut, will neo hang in air for 10 seconds without any
support?

If length of rope is x meter and speed of compression waves in
medium(rope) is y m/s then will object hang in air for x/y seconds?

If yes, why gravity wait for compression waves to travel within rope?
How does gravity communicate with compression waves?

[Rama]

[Androcles]

"Rama" <Ra...@Live.In> wrote in message
news:df98e433-501f-4b2d...@kw17g2000pbb.googlegroups.com...

Why you call stretch "compression"?
Stretch pull, compression push.
Neo not push helicopter up.

[Rama]

On May 19, 2:22 pm, "Androcles" <M...@May.2012> wrote:
> "Rama" <R...@Live.In> wrote in message

What do you mean?

[Helmut Wabnig]

I suggest you try it.


w.

[Rama]

On May 19, 2:22 pm, "Androcles" <M...@May.2012> wrote:

> "Rama" <R...@Live.In> wrote in message

What do you mean?

[Androcles]

"Rama" <Ra...@Live.In> wrote in message

news:5e02bd0f-1863-4f32...@n5g2000pbg.googlegroups.com...

=====================
Not if yes. Gravity not wait. Gravity not communicate. Gravity not give a
shit.
You idiot.

[Rama]

On May 19, 2:22 pm, "Androcles" <M...@May.2012> wrote:

> "Rama" <R...@Live.In> wrote in message

What do you mean?

[Rama]

On May 19, 2:37 pm, "Androcles" <M...@May.2012> wrote:
> "Rama" <R...@Live.In> wrote in message
>
> news:5e02bd0f-1863-4f32...@n5g2000pbg.googlegroups.com...
> On May 19, 2:22 pm, "Androcles" <M...@May.2012> wrote:
>
>
>
>
>
> > "Rama" <R...@Live.In> wrote in message
>
> >news:df98e433-501f-4b2d...@kw17g2000pbb.googlegroups.com...>
> > Stationary helicopter in air. Neo hanging in air with 1 km long rope.
> > > One end of rope attached to helicopter and other end in hands of neo.
> > > Suppose speed of compression waves in rope is 100 m/s. If rope at
> > > helicopter end is cut, will neo hang in air for 10 seconds without any
> > > support?
>
> > > If length of rope is x meter and speed of compression waves in
> > > medium(rope) is y m/s then will object hang in air for x/y seconds?
>
> > > If yes, why gravity wait for compression waves to travel within rope?
> > > How does gravity communicate with compression waves?
>
> > Why you call stretch "compression"?
> > Stretch pull, compression push.
> > Neo not push helicopter up.
>
> What do you mean?
> =====================
> Not if yes. Gravity not wait. Gravity not communicate. Gravity not give a
> shit.
> You idiot.

Does that mean neo will start falling at EXACTLY same moment rope at
helicopter end is cut? Information across rope travels instantaneously?

[dlzc]

Dear Rama:

On Saturday, May 19, 2012 12:09:38 PM UTC-7, Rama wrote:
> Stationary helicopter in air. Neo hanging in
> air with 1 km long rope. One end of rope
> attached to helicopter and other end in hands
> of neo. Suppose speed of compression waves in
> rope is 100 m/s.

That is like sponge rubber.

> If rope at helicopter end is cut, will neo hang
> in air for 10 seconds without any support?

The system of Neo-and-rope fall when no longer connected to helicopter. The propagation speed only describes how fast the rope comes towards Neo. Neo will approach the far end of the rope based on what the rope's mass-per-unit length is. The system's center of mass will appear to drop when released

David A. Smith

[Androcles]

"Rama" <Ra...@Live.In> wrote in message

news:49979183-9979-4a37...@l5g2000pbo.googlegroups.com...

================================================
Rope at helicopter end start falling at EXACTLY same moment rope at
helicopter end is cut, Neo start falling at EXACTLY same moment,
rope not compresses.

[Rama]

dlzc wrote:
> Dear Rama:
>
> On Saturday, May 19, 2012 12:09:38 PM UTC-7, Rama wrote:
> > Stationary helicopter in air. Neo hanging in
> > air with 1 km long rope. One end of rope
> > attached to helicopter and other end in hands
> > of neo. Suppose speed of compression waves in
> > rope is 100 m/s.
>
> That is like sponge rubber.
>
> > If rope at helicopter end is cut, will neo hang
> > in air for 10 seconds without any support?
>
> The system of Neo-and-rope fall when no longer connected to helicopter.

So you mean neo will start falling at EXACTLY same moment rope at
helicopter is cut. That means info about rope cut at helicopter end
travels to neo(who is 1 km away) instantaneously. You want to say this?

[Rama]

So as neo starts falling at EXACTLY same moment the rope at helicopter
end is cut and as length of rope between helicopter end and neo is 1
km hence info about rope cut at helicopter end travels across rope to
neo instantaneously. But FTL info travel is not allowed.

What do you say?

[Rama]

[alie...@gmail.com]

On May 19, 12:09 pm, Rama <R...@Live.In> wrote:
> Stationary helicopter in air. Neo hanging in air with 1 km long rope.

Rope stretches. Was it 1 km long before Neo used it for support, or
was it shorter so that Neo's weight stretches it to 1 km? Not that it
really matters; what matters is that the rope is stretched.

> One end of rope attached to helicopter and other end in hands of neo.
> Suppose speed of compression waves in rope is 100 m/s. If rope at
> helicopter end is cut, will neo hang in air for 10 seconds without any
> support?

"Compression waves" in rope? No such thing; what you want is the
rate at which stretched rope relaxes to its original length. That
varies with the material the rope is made of, how it is twisted, etc.

Anyway, no, Neo will not obey "cartoon physics"- you are erroneously
seeing Neo suspended from the free, upper end of the rope, which you
must remember is *falling*. The helicopter, the rope, and Neo all feel
the force of gravity. Neo and the rope start to fall instantly the
rope is cut, which also releases the tension on the rope. The rope
immediately begins to return to its unstretched length, putting an
upward force component on Neo, slightly slowing his fall rate until
the rope reaches its original, unstretched length, thus you must see
Neo as being effectively suspended from the center of mass of the
rope, which is *falling*. The free upper end of the rope falls
*faster* than it would if it were not under tension. The center of
mass of the Neo/rope system falls at the same rate anything else
would.


Mark L. Fergerson

[Rama]

[hanson]

"Rama" <Ra...@Live.In> wrote:
"Androcles" <M...@May.2012> wrote:
> "Rama" <R...@Live.In> wrote in message
> "Androcles" <M...@May.2012> wrote:
> > "Rama" <R...@Live.In> wrote in message
>

"Rama" <R...@Live.In> wrote:
> > Stationary helicopter in air. Neo hanging in air with 1 km long rope.
> > > One end of rope attached to helicopter and other end in hands of neo.
> > > Suppose speed of compression waves in rope is 100 m/s. If rope at
> > > helicopter end is cut, will neo hang in air for 10 seconds without any
> > > support?
> > > If length of rope is x meter and speed of compression waves in
> > > medium(rope) is y m/s then will object hang in air for x/y seconds?
> > > If yes, why gravity wait for compression waves to travel within rope?
> > > How does gravity communicate with compression waves?
>

Andro wrote:
> > Why you call stretch "compression"?
> > Stretch pull, compression push.
> > Neo not push helicopter up.
>

Rama wrote:
> What do you mean?

>
Andro wrote:
> Not if yes. Gravity not wait. Gravity not communicate.

>L Gravity not give a shit.
> You idiot.

>
Rama wrote:
Does that mean neo will start falling at EXACTLY same moment rope at
helicopter end is cut? Information across rope travels instantaneously?
>

hanson wrote:
That all depends on who "neo" is and what "neo" does...
Is it neo-con, neo-nazi, neolith, near earth object, Keanu Reaves,
neoprene, neodymium, neoplasm, neonatal, neozoic, neo-neo?
>
ROTFLMAO... ahahahaha... ahahahanson

[LaLALa]

On May 19, 3:42 pm, Rama <mr.ra...@googlemail.com> wrote:

>
> So you mean neo will start falling at EXACTLY same moment rope at
> helicopter is cut. That means info about rope cut at helicopter end
> travels to neo(who is 1 km away) instantaneously. You want to say this?

Mr. Rama, I believe you are absolutely right. Neo will take a little
bit before falling. You can think of each bit of rope as a little
spring so that the whole rope is like a chain of little springs. If we
like we can mentally divide up the rope into little decimeter segments
and number them under the cut all the way down to Neo like segment 1,
2, 3 and so on. Before the cut segment 2 does not fall because segment
1 is holding it up. Segment 1 applies a force on segment 2 because it
is stretched a little. I do not remember whether this law is Young's
law or Hooke's law. But I remember that it is that the restoring force
is proportion to its stretch. In my thinking segment 1 won't stop
pulling on segment 2 until the other end has moved a little so that it
is not so stretched. When segment 1 is stretched a little less then
the force holding up segment 2 will start to decrease and so then the
top of segment 2 will begin to fall and so segment 2 will be less
stretched so it will pull a little less hard on segment 3 and so on.

In my mind if this really were a chain of little springs and I moved
the top end of spring 1 a little then this would result in some kind
of wave or signal pulse traveling down the chain of springs. It may be
very possible that in a rope this traveling would be connected to the
speed of sound in the rope. It makes much sense to me because sound
after all starts with a little displacement at one end.

I don't believe Neo begins to fall until segment 10 000 no longer
feels held up by segment 9 999 and that's when segment 10 000 starts
to fall too. That would be just before Neo starts to fall.

I think one question that would come out of this is what if Neo
weren't on the end of the rope at all? What if it were just a rope
hanging there? By the thinking above I would have to believe that the
top of the rope starts to fall before the bottom of the rope does. Is
this possible? I think it is. Here is how I think about it. With the
rope just hanging there is still a force that stretches the rope -- it
is the force of the helicopter pulling on the top end equal to the
weight of the rope. When the rope is cut I think what must happen is
that the center of mass of the rope must start falling with
acceleration 9.8 m/s/s. That is Newton's second law. But this can be
satisfied even if the bottom of the rope does not start moving right
away. This can happen with the rope getting shorter because it is less
stretched so that the center of mass moves because only the top moves.
As the rope relaxes the top of the rope surely accelerates FASTER than
9.8 m/s/s. This is because there is no force pulling up on the top of
the rope but there is both the weight of that part of the rope AND the
stretch force of all the rope under it pulling it down. By this
thinking the behavior of the rope is that the middle of the rope is
accelerating down at 9.8 m/s/s and the top of the rope is accelerating
downward much faster than 9.8 m/s/s and the bottom of the rope is
accelerating down at must slower than 9.8 m/s/s. So the top of the
rope could conceivable catch up with the bottom of the rope as the
whole rope falls. This makes sense to me because that is the kind of
whiplash that is so dangerous when a taut cable breaks. It is not the
end far from the break that is dangerous. It is the end near the break
that can be flying at supersonic speeds and can kill people.

If what I am thinking is right then Neo won't start falling right away
but he might be killed by the top of the rope coming down and hitting
him very hard in the head. But someone who is a scientist might tell
you that I am full of garbage and that nothing I have told you is
right.

[Androcles]

"Rama" <Ra...@Live.In> wrote in message

news:b1170d34-8dcb-45dc...@oo8g2000pbc.googlegroups.com...

=========================================
I say Einstein was an idiot, but that has nothing to do with
helicopters and ropes.

[dlzc]

Dear Rama:

Have you never watched video of people bungie jumping, who's bungie broke?

Neo does not accelerate downwards at 9.81 m/sec^2 with respect to the Earth right away, but the entire system responds to the loss of support.

Remember, the helicopter is the one accelerating at 9.81 m/sec^2 off its default elliptical orbit. Neo and the rope are no longer accelerated by the helicopter's rotor, the instant the rope is cut. The center of mass of the Neo + rope system just follows its orbit until displaced by wind or Earth (and maybe Fire too...).

David A. Smith

[Katsumoto Sakuraba]

On May 19, 11:35 pm, LaLALa <lajourney...@gmail.com> wrote:
> On May 19, 3:42 pm, Rama <mr.ra...@googlemail.com> wrote:
>
>
>
> > So you mean neo will start falling at EXACTLY same moment rope at
> > helicopter is cut. That means info about rope cut at helicopter end
> > travels to neo(who is 1 km away) instantaneously. You want to say this?
>
> Mr. Rama, I believe you are absolutely right. Neo will take a little
> bit before falling. You can think of each bit of rope as a little
> spring so that the whole rope is like a chain of little springs.

[snip crap]

> hanging there? By the thinking above I would have to believe that the
> top of the rope starts to fall before the bottom of the rope does. Is
> this possible? I think it is.

only if the rope is short, otherwise higher gravity
at bottom end and close to zero at the top

the centrifugal force may even hold the rope
suspended

[Katsumoto Sakuraba]

or rather how to not give an answer

good bye

[Katsumoto Sakuraba]

how you know that, can you show
an animation ?

put some numbers and show your
animation of the rope

[xxein]

xxein: It doesn't. they are two separate things. Neo will instantly
fall because gravity at his position says so. Yes, the rope
compressing has an effect as long as Neo is holding it. But that has
no direct connection to gravity. Neither does a trampoline. It only
affects a motion - not the gravity at Neo's point.

[Androcles]

"Rama" <Ra...@Live.In> wrote in message

news:2c57e8d2-ccba-4e82...@n8g2000pbv.googlegroups.com...

====================================
I say you wasting your time posting same more than once,
I watch TV and not answer you until I'm ready to.

[Katsumoto Sakuraba]

you too, do an animation

good bye

[Helmut Wabnig]

You are a genius.
Let them unroll a rope from the ISS space station.
Which direction will it go?


w.

[Katsumoto Sakuraba]

exactly, the international play station is a
suspended rope !!!

good bye

[Paul B. Andersen]

On 19.05.2012 21:16, Rama wrote:
> Stationary helicopter in air. Neo hanging in air with 1 km long rope.
> One end of rope attached to helicopter and other end in hands of neo.
> Suppose speed of compression waves in rope is 100 m/s. If rope at
> helicopter end is cut, will neo hang in air for 10 seconds without any
> support?

Yes.
But the rope is still supporting him during those 10 seconds.

> If length of rope is x meter and speed of compression waves in
> medium(rope) is y m/s then will object hang in air for x/y seconds?

Yes.

> If yes, why gravity wait for compression waves to travel within rope?
> How does gravity communicate with compression waves?

Neo will fall when the force exerted on him
by the rope disappears, which will happen x/y seconds
after the rope is cut.

The rope will be stretched before it is cut.
So let's imagine the rope consists of of a number
of masses (m) connected by expanded springs (|).

H H H H H
m1
| m1
m2 m2 m1
| | m2 m1
m3 m3 m3 m2 m1
| | | m3 m2
m4 m4 m4 m4 m3
N N N N m4
N
t 1 2 3 4 5

t = 1: the rope is cut at the helicopter H
t = 2: the upper string will relax, accelerating m1 downwards.
The reaction force will keep m2 in place.
t = 3: m1 is now falling. The next spring will relax,
accelerating m2 downwards.
The reaction force will keep m3 in place.
t = 4: m1 and m2 are falling. The next string will relax, etc.
t = 5: the whole rope and Neo is falling.

The information "rope cut" will travel through the rope
with the speed of sound y in the rope. There is no way
Neo can fall before this information has reached him
after the time x/y.

What is holding Neo up during that time, is the reaction
force as the stretched rope is relaxing from the top down.

Note:
This is not related to what usually is meant by
the frase "the speed of gravity".

--
Paul

http://www.gethome.no/paulba/

[Rama]

Consider the 'rope' as space line/spring between earth and sun. If
this 'rope' at Sun is cut(sun cease to exist), how long will it take
for earth to know?

-Abhi.

[Rama]

[Androcles]

"Rama" <Ra...@Live.In> wrote in message

news:72e7414a-d511-455c...@to5g2000pbc.googlegroups.com...

==========================================
About 93,000,000 miles long.

[Rama]

http://boldlentil.files.wordpress.com/2008/06/helicopter_w_6-swat-guys.jpg

You think these 6 swat guys will hang in air without support for
sometime?

ROFL!

[hanson]

7x "Rama" <Ra...@Live.In> wrote:

6x "Androcles" <M...@May.2012> wrote:
>
> > > > "Rama" <R...@Live.In> wrote in message

Rama wrote:
Consider the 'rope' as space line/spring between earth and sun. If
this 'rope' at Sun is cut(sun cease to exist), how long will it take
for earth to know?
-Abhi.
>

hanson wrote:
Rama, in your splendid street corner performance here,
you appear to suffer from Neo-Einstein Dingleberryism
which causes you to engage in furious & protracted
mental masturbations about ropes whose material
properties nor lengths do NOT exist anywhere in the
know universe...
>
Einstein too did masturbate over his light cones,
space-time, his younger twin, rigid sticks, rubber rulers,
shrinking barns and trains that roll at 10'000 miles/sec...
all items that do NOT exist anywhere in the know universe...
>
See Rama, you are in august company. Carry on.
You have become a Neo-Einstein Dingleberry now.
Thanks for the laughs, Rama you Dreidel,.... ahahahaha...
hahahahahanson

[Roy Culley]

In article <e2c0b32f-39d0-46a4...@pr3g2000pbb.googlegroups.com>,

"nu...@bid.nes" <alie...@gmail.com> writes:
> Anyway, no, Neo will not obey "cartoon physics"- you are erroneously
> seeing Neo suspended from the free, upper end of the rope, which you
> must remember is *falling*. The helicopter, the rope, and Neo all feel
> the force of gravity. Neo and the rope start to fall instantly the
> rope is cut, which also releases the tension on the rope. The rope
> immediately begins to return to its unstretched length, putting an
> upward force component on Neo, slightly slowing his fall rate until
> the rope reaches its original, unstretched length, thus you must see
> Neo as being effectively suspended from the center of mass of the
> rope, which is *falling*. The free upper end of the rope falls
> *faster* than it would if it were not under tension. The center of
> mass of the Neo/rope system falls at the same rate anything else
> would.

Slinky Drop Answer:
<http://www.youtube.com/watch?v=eCMmmEEyOO0>

[alie...@gmail.com]

On May 20, 12:57 pm, r...@nodomain.none (Roy Culley) wrote:
> In article <e2c0b32f-39d0-46a4-9d68-3724d2aeb...@pr3g2000pbb.googlegroups.com>,

Better answer:

http://www.youtube.com/watch?feature=endscreen&NR=1&v=oKb2tCtpvNU

Note that in the audio it is claimed that the ball remains
stationary until the slinky collapses. But actually watching the video
it is easy to see the ball *falling* while the slinky collapses. Watch
the ball move WRT the little white spot on the ground at around 1:00
to 1:08.

Mark L. Fergerson

[Helmut Wabnig]

Yes it is moving slightly downwards at a rather constand small speed
which tells it's not free fall. Could it be an experimenter's error in
that he did now wait long enough until the ball stopped oscillating
and we just see that oscillating movement?

w.

[mar...@gmail.com]

It's sad that in all this noise you are unable to notice a legit answer, and your intelligence doesn't seem to help you recognize it either. Yes, those guys will hang there for some very short time, too short to notice with the naked eye. We are talking about approx 4ms or less. It may be noticeable on a very high-speed recording.

The "speed" of gravity is thought to be c, same as light, i.e. if Sun was to vanish suddenly, Earth will only notice it some 8 min later.

[Androcles]

<mar...@gmail.com> wrote in message
news:f166088d-b75a-4ab4...@googlegroups.com...

==========================================
ROFL!
"the velocity of light in our theory plays the part, physically, of an
infinitely great velocity." -- Albert Fuckwit Einstein.

Marcuac plays the part, physically, of an infinitely great babbling cretin.

[Unified_Perspective]

On May 19, 3:09 pm, Rama <R...@Live.In> wrote:
> Stationary helicopter in air. Neo hanging in air with 1 km long rope.
> One end of rope attached to helicopter and other end in hands of neo.
> Suppose speed of compression waves in rope is 100 m/s. If rope at
> helicopter end is cut, will neo hang in air for 10 seconds without any
> support?
>

> If length of rope is x meter and speed of compression waves in
> medium(rope) is y m/s then will object hang in air for x/y seconds?
>

> If yes, why gravity wait for compression waves to travel within rope?
> How does gravity communicate with compression waves?

Neo has weight, helicopter lift = tension in rope.
Neo already falling (has weight) when rope is cut.
Release of tension in rope and weight of rope makes Neo fall a tiny
bit faster.
Hoth reach terminal velocity. Drag = weight
Neo goes splat. Momentum > Impact
Rope coils on chest.
Both bodies at rest.
Equilibrium is peaceful.
Falling from helicopters - not so much.

Actually this example does explain why gravity APPEARS to act
instantaneously. The Earth's field is very large and preexists the cut
of the rope.

For planets and orbits the full effects are more apparent. G the field
is largely constant. g the force varies with inverse square of
distance, and typically the distance also varies over time. Enough
information that very very smart people could figure it out. With
their help the rest of us - get it. Hope you join the crowd someday>
It is more helpful than hanging around spreading tension, and more
peaceful as well.

[alie...@gmail.com]

On May 20, 1:59 pm, Helmut Wabnig <hwabnig@.- --- -.dotat> wrote:
> On Sun, 20 May 2012 13:28:03 -0700 (PDT), "n...@bid.nes"

There are an undetermined (small) number of high-speed frames just
before release, but the ball appears stationary vertically in all of
them (to me).

Hard to tell if it's accelerating in the very few frames during
collapse.


Mark L. Fergerson

[Chris Richardson]

On Sun, 20 May 2012 21:57:23 +0200, Roy Culley wrote:

>
> Slinky Drop Answer:
> <http://www.youtube.com/watch?v=eCMmmEEyOO0>
>

Thanks to the OP for this problem.

The definitive answer seems to be here:

http://danielwalsh.tumblr.com/post/11566016253/explaining-an-astonishing-slinky

[Chris Richardson]

On Mon, 21 May 2012 02:48:21 +0000, Chris Richardson wrote:

>
> The definitive answer seems to be here:
>
> http://danielwalsh.tumblr.com/post/11566016253/explaining-an-astonishing-slinky
>

An even more definitive answer:

http://arxiv.org/abs/1006.5629

Mathematics trumps intuition.

[Rama]

For the moment I am speechless...

http://www.youtube.com/watch?v=JsytnJ_pSf8

[jem]

LaLALa wrote:
> On May 19, 3:42 pm, Rama<mr.ra...@googlemail.com> wrote:
>
>>
>> So you mean neo will start falling at EXACTLY same moment rope at
>> helicopter is cut. That means info about rope cut at helicopter end
>> travels to neo(who is 1 km away) instantaneously. You want to say this?
>
> Mr. Rama, I believe you are absolutely right. Neo will take a little
> bit before falling. You can think of each bit of rope as a little

> spring so that the whole rope is like a chain of little springs. If we
> like we can mentally divide up the rope into little decimeter segments
> and number them under the cut all the way down to Neo like segment 1,
> 2, 3 and so on. Before the cut segment 2 does not fall because segment
> 1 is holding it up. Segment 1 applies a force on segment 2 because it
> is stretched a little. I do not remember whether this law is Young's
> law or Hooke's law. But I remember that it is that the restoring force
> is proportion to its stretch. In my thinking segment 1 won't stop
> pulling on segment 2 until the other end has moved a little so that it
> is not so stretched. When segment 1 is stretched a little less then
> the force holding up segment 2 will start to decrease and so then the
> top of segment 2 will begin to fall and so segment 2 will be less
> stretched so it will pull a little less hard on segment 3 and so on.
>
> In my mind if this really were a chain of little springs and I moved
> the top end of spring 1 a little then this would result in some kind
> of wave or signal pulse traveling down the chain of springs. It may be
> very possible that in a rope this traveling would be connected to the
> speed of sound in the rope. It makes much sense to me because sound
> after all starts with a little displacement at one end.
>
> I don't believe Neo begins to fall until segment 10 000 no longer
> feels held up by segment 9 999 and that's when segment 10 000 starts
> to fall too. That would be just before Neo starts to fall.
>
> I think one question that would come out of this is what if Neo
> weren't on the end of the rope at all? What if it were just a rope

> hanging there? By the thinking above I would have to believe that the
> top of the rope starts to fall before the bottom of the rope does. Is

> this possible? I think it is. Here is how I think about it. With the
> rope just hanging there is still a force that stretches the rope -- it
> is the force of the helicopter pulling on the top end equal to the
> weight of the rope. When the rope is cut I think what must happen is
> that the center of mass of the rope must start falling with
> acceleration 9.8 m/s/s. That is Newton's second law. But this can be
> satisfied even if the bottom of the rope does not start moving right
> away. This can happen with the rope getting shorter because it is less
> stretched so that the center of mass moves because only the top moves.
> As the rope relaxes the top of the rope surely accelerates FASTER than
> 9.8 m/s/s. This is because there is no force pulling up on the top of
> the rope but there is both the weight of that part of the rope AND the
> stretch force of all the rope under it pulling it down. By this
> thinking the behavior of the rope is that the middle of the rope is
> accelerating down at 9.8 m/s/s and the top of the rope is accelerating
> downward much faster than 9.8 m/s/s and the bottom of the rope is
> accelerating down at must slower than 9.8 m/s/s. So the top of the
> rope could conceivable catch up with the bottom of the rope as the
> whole rope falls. This makes sense to me because that is the kind of
> whiplash that is so dangerous when a taut cable breaks. It is not the
> end far from the break that is dangerous. It is the end near the break
> that can be flying at supersonic speeds and can kill people.
>
> If what I am thinking is right then Neo won't start falling right away
> but he might be killed by the top of the rope coming down and hitting
> him very hard in the head. But someone who is a scientist might tell
> you that I am full of garbage and that nothing I have told you is
> right.

Well, Mr. Lala, although you're clearly no scientist, that does look
like a pretty good way to "think about it".

[G=EMC^2]

Gravity is continuos We are immersed in its field(web). Like an
octopus born at the bottom of the ocean floor with its pressure all
around it. We are shaped by gravity. We are killed by gravity. We
walk because of gravity. My thinking about gravity came when I got on
my birthday a gyro. I was 8 I still have it and still get it
spinning. It still amazes me. Never forget that G=EMC^2. TreBert

[mar...@gmail.com]

Nice video! Does it answer your question? Let me guess, you want to see if it does the same thing when there's a mass hanging at the end...

Just because we can't always predict or have a good intuition about the way Nature works it doesn't mean we should be close-minded about the possibilities. And when others do know, we shouldn't just reject their explanation outright, simply because we can't understand the explanation or can't test it for ourselves. Hint on Special and General Relativity, in particular.

[Chris Richardson]

On Sun, 20 May 2012 22:51:48 -0700, Rama wrote:

>
> For the moment I am speechless...
>

Why speechless? There is nothing unusual about the situation.
We have an equilibrium condition as the spring hangs freely.
Each portion of the spring is hanging motionless from the portion
immediately above it due to the tension (torsion) developed at
that point. This condition is maintained even though the top
is released and begins to accelerate downwards.

We could even eliminate gravity from this experiment, because
apparent levitation in a gravity field is spooky to a lot of
people.

Imagine a horizontal table, with a frictionless surface, upon
which one end of a spring, the left end, is attached. The opposite
end of the spring, the right end, is subject to a constant force.
This can be done by attaching a weight to the right end and allowing
the weight to hang over the table end (via a pulley and string).
The constant force will stretch the spring to an equilibrium condition.
If the left of the spring is suddenly released, the right end
should remain motionless for a time as in the original
experiment.

Someone should make a video of this horizontal case.

[Rama]

Damn! Where from you dropped?

It seems Einstein is winning.

[G=EMC^2]

Light passing through the event horizon it moves faster than c ,but
tying to get out it can't go faster than c. Get the picture TreBert

[Androcles]

"Rama" <Ra...@Live.In> wrote in message

news:4083b487-f85c-490e...@oo8g2000pbc.googlegroups.com...

The centre of the slinky is accelerated down at 32 fps/s.
The top of the slinky is pulled down by both gravity and
the tension in the spring, the bottom of the slinky is
pulled down by gravity and up by the tension in the
spring. Einstein loses.

[Paul B. Andersen]

>> the phrase "the speed of gravity".

>
> http://boldlentil.files.wordpress.com/2008/06/helicopter_w_6-swat-guys.jpg
>
> You think these 6 swat guys will hang in air without support for
> sometime?

No, but I think the rope will cease to support them
1-2 ms after it is cut at the helicopter.

> ROFL!

Why do you ask when you won't bother to read the answer?
If you had read it, you would understand that I was right.
Unless you are too stupid to recognise a sensible answer, that is.
Are you?

--
Paul

http://www.gethome.no/paulba/

[Thomas Heger]

Am 21.05.2012 02:45, schrieb Unified_Perspective:
> On May 19, 3:09 pm, Rama<R...@Live.In> wrote:
>> Stationary helicopter in air. Neo hanging in air with 1 km long rope.
>> One end of rope attached to helicopter and other end in hands of neo.
>> Suppose speed of compression waves in rope is 100 m/s. If rope at
>> helicopter end is cut, will neo hang in air for 10 seconds without any
>> support?
>>
>> If length of rope is x meter and speed of compression waves in
>> medium(rope) is y m/s then will object hang in air for x/y seconds?
>>
>> If yes, why gravity wait for compression waves to travel within rope?
>> How does gravity communicate with compression waves?
>
> Neo has weight, helicopter lift = tension in rope.
> Neo already falling (has weight) when rope is cut.
> Release of tension in rope and weight of rope makes Neo fall a tiny
> bit faster.
> Hoth reach terminal velocity. Drag = weight
> Neo goes splat. Momentum> Impact
> Rope coils on chest.
> Both bodies at rest.
> Equilibrium is peaceful.
> Falling from helicopters - not so much.
>
> Actually this example does explain why gravity APPEARS to act
> instantaneously. The Earth's field is very large and preexists the cut
> of the rope.
>

No, the example does not explain the speed of gravity. Actually it has
nothing to do with that question.
A man hangs on a very long rope. Question: after the rope is cut, how
fast is this information transferred through the rope? (that is somehow
the question asked).

There is no speed of gravity involved, but speed of elastic reactions in
a rope. (certainly this is propagating at sound-speed).

Speed of gravity could be estimated from planetary movement. If gravity
had a velocity, the gravitational field should kind of 'trail back'. the
apparent centre of gravity should be behind the real planet.

But, as far as I know, this is not the case and gravity appears to
distribute instantaneous.

So, most likely, gravity does not need to move, but space itself has the
feature we call gravity with or without a planet to attract (in other
words: it does not move - or 'is there already').

This would fit nicely to GR, but not to the standard model, that
requires 'exchange bosons' ('gravitons').

TH

[dlzc]

Dear Thomas Heger:

On Monday, May 21, 2012 1:40:06 PM UTC-7, Thomas Heger wrote:
...

> This would fit nicely to GR, but not to the
> standard model, that requires 'exchange bosons'
> ('gravitons').

Virtual particles like gravitons travel all possible speeds (no c limit) and all possible paths. No problem with "instantaneous".

David A. Smith

[hanson]

Hey, Paul!... it's good to have you back!
There is NOTHING better then s.p.
All the other forums are feeble laments
about textbook physics and feel like a
walk through the grave yard.
Right or wrong, s.p is where it's at!
Welcome back, Professor Draper!
ahahaha... hahahahahanson
>
"PD" <thedrap...@gmail.com> wrote

On May 19, 3:40 pm, "Androcles" <M...@May.2012> wrote:

> Rope at helicopter end start falling at EXACTLY same moment rope at
> helicopter end is cut, Neo start falling at EXACTLY same moment,
> rope not compresses.

Are you sure, Mr. Parker? It seems to me this doesn't match either
Newtonian physics or observational measurement.
http://en.wikisource.org/wiki/The_Foundation_of_the_Generalised_Theory_of_Relativity
It is definitely a pity that the Slinky is not a rope, the ball is not
a movie character, and the person's hand is not a helicopter.

[Abhi]

On May 20, 2:57 pm, r...@nodomain.none (Roy Culley) wrote:
> In article <e2c0b32f-39d0-46a4-9d68-3724d2aeb...@pr3g2000pbb.googlegroups.com>,

Thank you and thanks everyone. This video destroyed my 12 year old
intution.

But this propagation delay of information can be used to create excess
energy from... gravity assist!

[Abhi]

On May 20, 2:57 pm, r...@nodomain.none (Roy Culley) wrote:
> In article <e2c0b32f-39d0-46a4-9d68-3724d2aeb...@pr3g2000pbb.googlegroups.com>,

[LaLALa]

On May 24, 12:34 pm, Abhi <R...@Live.In> wrote:

>
> Thank you and thanks everyone. This video destroyed my 12 year old
> intution.
>

This is a fine example of why intuition should be mistrusted as a
guide to understanding and why scientists rely so much on careful
measurement.

This makes some people despair and they worry that if they cannot
intuit the truth then it is hopeless to understand anything. But this
is not so. What is so is that intuition has to grow and to change in
conformance to what is actually observed. Since intuition was in
conflict with the video then the next thing to do is to ask how can I
change my intuition about this situation so that the video is not so
shocking? In my first reply to Mr. Rama I tried very hard to examine
my intuition about these things and you can see that I got it lucky
and was able to provide an accurate prediction of what would happen to
Neo in a way that is also intuitive to me. If I can do that than just
about anybody can too.

[Paul B. Andersen]

So maybe you have stopped laughing at the answer
I gave you?
http://tinyurl.com/c9ex6uf

--
Paul

http://www.gethome.no/paulba/

[Paul B. Andersen]

It could be experimental error, but I don't think it is.
Note that this effect was only present when the tennis ball
was at the end, so I think the answer is found in the nature
of the spring. It will be mostly shear forces in the spring;
the wire in the spring is mainly twisted. The speed of sound
in this spring will be very slow.
But when the spring is extended very far, the wire in the spring
will be stretched as well as twisted, and when this stretch
is relaxed at the top, there will be a sound wave along the wire
in the spring. Longitudinal sound waves in steel propagates very
fast, 2 km/s or thereabout, so this wave will reach the ball
long before the other wave reaches it.

So the ball starts falling very quickly because the stretch in
wire is relaxed quickly, but since the stretch isn't very
much, the spring will be only a little longer when it
is relaxed, and the ball doesn't fall very far because of it.
The ball is free-falling only when the main sound wave reaches it.



--
Paul

http://www.gethome.no/paulba/

[Paul B. Andersen]

Do you think Einstein and Newton would disagree about
when Neo would start to fall?

This has nothing to do with relativity!
Why did you think it had?

--
Paul

http://www.gethome.no/paulba/

[Androcles]

"Paul B. Andersen" <som...@somwhere.no> wrote in message
news:jpm713$pl5$1...@news.albasani.net...

Quit boasting, Porky. Your long-winded explanation was too
boring to follow.

[Androcles]

"Paul B. Andersen" <som...@somwhere.no> wrote in message

news:jpm8d6$slu$1...@news.albasani.net...

What a load of crap! The top of the slinky accelerates at 2g, it is
pulled down by both gravity and tension in the spring. No bullshit
about sound waves needed.

[Androcles]

"Paul B. Andersen" <som...@somwhere.no> wrote in message

news:jpm8rb$tg2$1...@news.albasani.net...

It has everything to do with Galilean relativity!
Why do you hallucinate it doesn't?

[Tom Roberts]

I do think it is. Compare that motion to the motion of the tennis ball just
before release -- they look comparable to me.

But in the video I see, the slow-motion video is over at 0.52,
so that 1:00 to 1:08 is inconsistent with the video I see.



Tom Roberts

[Tom Roberts]

On 5/24/12 5/24/12 1:55 PM, LaLALa wrote:
> On May 24, 12:34 pm, Abhi<R...@Live.In> wrote:
>> Thank you and thanks everyone. This video destroyed my 12 year old
>> intution.
>
> This is a fine example of why intuition should be mistrusted as a
> guide to understanding and why scientists rely so much on careful
> measurement.

Yes. But intuition can be trained with experience. Upon hearing the question, my
immediate response was that the weight at the bottom (neo or a tennis ball)
would remain motionless until the news of the release at the top reached the
bottom, traveling at the speed of sound. So the videos reinforced my intuition.


Tom Roberts

[Thomas Heger]

How virtual are virtual particles?

If 'anything goes' than there should be something to discriminate 'these
things are pure fiction' from 'these things do exist'.

If you say 'graviton can travel at any possible speed', than the double
of some unbelievable fast pace must also be possible. .. and the double
of that, too.

In other words: gravitons travel at infinite pace.

But real things cannot travel at infinite speed, because than one thing
is here and at the other end of the universe at the same time. This
violates the idea of 'thing', what should be somehow located in space
and time.


TH

[dlzc]

Dear Thomas Heger:

On Sunday, May 27, 2012 3:19:28 PM UTC-7, Thomas Heger wrote:
> Am 22.05.2012 00:14, schrieb dlzc:
> > Dear Thomas Heger:
> >
> > On Monday, May 21, 2012 1:40:06 PM UTC-7, Thomas Heger wrote:
> > ...
> >> This would fit nicely to GR, but not to the
> >> standard model, that requires 'exchange bosons'
> >> ('gravitons').
> >
> > Virtual particles like gravitons travel all
> > possible speeds (no c limit) and all possible
> > paths. No problem with "instantaneous".
>

> How virtual are virtual particles?

They are proposed to suit quantum mechanics. As such, they have certain features.

> If 'anything goes' than there should be
> something to discriminate 'these things are
> pure fiction' from 'these things do exist'.

Sorry, but all of Science is "pure fiction" by some accountings. All we have is our best guesses, and the steady hand of Nature.

> If you say 'graviton can travel at any possible
> speed',

... not "any", "all".

> than the double of some unbelievable fast pace
> must also be possible. .. and the double
> of that, too.

And the same for half, and half. Inclusive of infinity and zero. Inclusive of towards the target particle, and directly away from it.

> In other words: gravitons travel at infinite pace.

They travel all possible speeds, yes.

> But real things cannot travel at infinite speed,

... hence "virtual".

> because than one thing is here and at the other
> end of the universe at the same time. This
> violates the idea of 'thing',

Not really.

> what should be somehow located in space and time.

Fits entwinement pretty well though, doesn't it? Also fits really well with the source of inertia, according to Mach. Also fits pretty well with "self-interference", and a number of other phenomenon. So a better question might be "How real is localizable, finite?"

David A. Smith

[Thomas Heger]

Am 28.05.2012 00:58, schrieb dlzc:
> Dear Thomas Heger:
>
> On Sunday, May 27, 2012 3:19:28 PM UTC-7, Thomas Heger wrote:
>> Am 22.05.2012 00:14, schrieb dlzc:
>>> Dear Thomas Heger:
>>>
>>> On Monday, May 21, 2012 1:40:06 PM UTC-7, Thomas Heger wrote:
>>> ...
>>>> This would fit nicely to GR, but not to the
>>>> standard model, that requires 'exchange bosons'
>>>> ('gravitons').
>>>
>>> Virtual particles like gravitons travel all
>>> possible speeds (no c limit) and all possible
>>> paths. No problem with "instantaneous".
>>
>> How virtual are virtual particles?
>
> They are proposed to suit quantum mechanics. As such, they have certain features.
>

'Gravitons' belong to the standard model of QM. But I think it's fair to
ask: what is meant with 'graviton'?

If someone says, gravity is in a way dependent on such entities, than it
must be explained, why and how that should happen. (Otherwise you can
say, fairies transfer gravitation.)

So: are these entities 'things'?

A thing should have certain characteristics: e.g. a thing should be
countable.

For example: are gravitons small or more very big?

The number pi on the other hand would certainly suit QM. But pi is not a
thing. Its a number.

Hence, not everything, that fits to some kind of worldview is
necessarily an entity, we would find in nature.

>> If 'anything goes' than there should be
>> something to discriminate 'these things are
>> pure fiction' from 'these things do exist'.
>
> Sorry, but all of Science is "pure fiction" by some accountings. All we have is our best guesses, and the steady hand of Nature.

No, science is certainly not 'pure fiction'.
There is the scientific method, that tells us, what is scientific and
what is not.
I agree to 'best guesses' - in a way. But I have doubt, that 'gravitons'
belong to that category.

>> If you say 'graviton can travel at any possible
>> speed',
>
> ... not "any", "all".
>

Sorry, but English is a second language for me and certain linguistic
problems are inevitable. (Here: the difference between all and any).

>> than the double of some unbelievable fast pace
>> must also be possible. .. and the double
>> of that, too.
>
> And the same for half, and half. Inclusive of infinity and zero. Inclusive of towards the target particle, and directly away from it.

Agreed.

If all speeds are possible, than gravitons should be able to move slow,
too, hence with velocities from zero to infinity.

But that is like no information, because this means, gravitons have no
limitations in velocity. Only it is not possible to test such a
statement, if the existence is not already proven.

Gravitons might exist, but we can't say if they do. If they exist, than
they should have some limitations of some kind.

Otherwise you cannot say, whether a certain entities is a graviton or not.

TH

[dlzc]

Dear Thomas Heger:

On Monday, May 28, 2012 1:37:51 PM UTC-7, Thomas Heger wrote:
...

> If all speeds are possible, than gravitons
> should be able to move slow, too, hence with
> velocities from zero to infinity.

Correct. As long as it net results to information transfer at c or less, it agrees with this Universe.

> But that is like no information, because this
> means, gravitons have no limitations in
> velocity.

... just like everything else in QM.

> Only it is not possible to test such a
> statement, if the existence is not already
> proven.

Gravitons have one big problem to me... they have to carry spacetime into the quantum realm. I don't see that happening.

> Gravitons might exist, but we can't say if
> they do. If they exist, than they should
> have some limitations of some kind.
>
> Otherwise you cannot say, whether a certain
> entities is a graviton or not.

How does gravitation get out of a black hole, if the quantum-interaction particles do not travel infinitely fast? You can clearly see a need for them, and the features they must have. But they are surely a work in progress.

David A. Smith

[Thomas Heger]

Well, if you want an answer, than possibly I can provide that.
I'm kind of hobby physicist, so my solution is a little amateurish. But
nevertheless I have one.

The idea is actually simple and very 'straight forward' - only a little
different.

I tried to connect GR and QM and started with GR. Assumption: if
relativity is somehow correct and QM, too, then there should be a
connection. I started with GR and tried to rebuild particles out of
spacetime.

After 'sieving' a lot of papers I found some similarities in the formula
of rotations with quaternions to the position-operator of
quantum-mechanics.

The idea is based on rotations, that are interlocked. The 'elements of
spacetime' twist their neighbour in a certain way. Matter in this
picture is a pattern or what I call 'structure' and the idea is called
'structured spacetime'.

I have produced a kind of book (what is still a google.doc presentation)
and you can find it here:
https://docs.google.com/present/view?id=dd8jz2tx_3gfzvqgd6


Actually it answers your question: how does gravity get out of a black hole?

The standard model of cosmology is too twisted, but let me try to
explain: imagine to fly to a black hole from Earth. You fly and fly and
fly, getting faster and faster and faster - relative to Earth. Relative
to the black hole you get slower and slower and slower (relatively),
since you catch up. But now the Earth seems to vanish in a black hole.

Blinck...the Earth is gone

and the navigation systems says: 'you have reached your destination'
(the black hole).

The area is just usual space.

Since the Earth has vanished in a black hole, we know what happens at
such a place: if you are co-moving, than nothing specific is happening.

TH

[Tom Roberts]

On 5/29/12 5/29/12 8:53 AM, dlzc wrote:
> How does gravitation get out of a black hole, if the quantum-interaction
> particles do not travel infinitely fast?

You are implicitly assuming that gravity "comes from something inside the black
hole". I see no need for that. Indeed, in GR this is not so.


Tom Roberts

[dlzc]

Dear Tom Roberts:

Gravitons are only required in quantum mechanics. Should QM ever successfully describe gravitation, and does so using exchange particles, they would have to come from "inside".

Agree GR requires no such thing.

David A. Smith