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Golden Boar
science forum Guru
Joined: 17 May 2005
Posts: 651
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 Posted: Thu Apr 20, 2006 5:26 pm Post subject:
About mass - the resistance to movement
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When people think of mass, they think of something they can reach out
and touch, but this idea is wrong. Mass is the resistance of an energy
packet to a change in its spacetime coordinates, or , more simply, mass
is resistance to movement.
A photon travels through the vacuum of spacetime at the constand speed
of c, the speed of light. All other particles travel through this
vacuum at less than c. This is becuase they have mass, or to put it
more correctly, they have a resistance to movement.
Since mass is the resistance to movement, this explains why there is no
negative mass.
Relative mass
An object moving through the air will experience drag. As the speed of
the object increases, the drag it experiences will increase as well.
It is similar with a particle moving through spacetime. As it's speed
is increased, the resistance to movement is also increased.
Since a photon's speed is constant, there is no change in its
resistance.
Questions
How do we know that an object at rest has mass if we have never brought
an object to rest?
Recent ideas about the vacuum suggest that it is not empty after all,
but filled with virtual particles, quantum fluctuations, etc. Could
these act like air molecules causing drag, to give rise to an increase
in relative mass?
When an object approaches the speed of light, time runs slower for that
object. Does this mean that a photon does not travel through the time
dimension? If so, could it be that travelling through the time
dimension gives an object mass? |
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Sam Wormley
science forum Guru
Joined: 30 Apr 2005
Posts: 1491
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| Posted: Thu Apr 20, 2006 5:52 pm Post subject:
Re: About mass - the resistance to movement
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Golden Boar wrote:
| Quote: | When people think of [inertial] mass, they think of something they can reach out
and touch, but this idea is wrong. [Inertial] Mass is the resistance of an energy
packet to a change in its spacetime coordinates, or , more simply, [inertial] mass
is resistance to movement.
A photon travels through the vacuum of spacetime at the constand speed
of c, the speed of light. All other particles [with mass] travel through this
vacuum at less than c. This is becuase they have [inertial] mass, or to put it
more correctly, they have a resistance to movement [ie inertia].
Since [inertial] mass is the resistance to movement, this explains why there is no
negative mass.
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Can you give a definition of "negative mass"?
| Quote: | Questions
How do we know that an object at rest has mass if we have never brought
an object to rest?
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Photons do not have mass, but they do have momentum. The proper, general
equation to use is E^2 = m^2c^4 + p^2c^2 For the photon, m=0 so E = pc
or p = E/c.
| Quote: |
Recent ideas about the vacuum suggest that it is not empty after all,
but filled with virtual particles, quantum fluctuations, etc. Could
these act like air molecules causing drag, to give rise to an increase
in relative mass?
|
Inertial mass is believed to be cause by the Higgs field pervading the
cosmos.
| Quote: |
When an object approaches the speed of light, time runs slower for that
object. Does this mean that a photon does not travel through the time
dimension? If so, could it be that travelling through the time
dimension gives an object mass?
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Quoting from pgs 391-392, "The Elegant Universe", Brian Greene (1999)
which includes:
"Then, the "speed through spacetime" is the magnitude of the
4-vector u, [((c^2 dt^2 - dx_bar^2)/(dt^2 - c^-2 dx_bar^2))]^0.5,
which is identically the speed of light, c. Now, we can rearrange
the equation c^2 (dt/dtau)^2 - (dx_bar/dtau)^2 = c^2, to be c^2
(dtau/dt)^2 + (dx_bar/dt)^2 = c^2. This shows than an increase in
an object's speed through space, [(dx_bar/dt)^2]^0.5 must be
accompanied by a decrease in dtau/dt, the latter being the object's
speed through time (the rate at which time elapses on its own
clock, dtau, as compared with that on our stationary clock, dt)".
This illustrates an increase in an object's speed through space must
be accompanied by a decrease in dtau/dt, the latter being the
object's speed through time, i.e., time dilation. |
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Golden Boar
science forum Guru
Joined: 17 May 2005
Posts: 651
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| Posted: Thu Apr 20, 2006 6:30 pm Post subject:
Re: About mass - the resistance to movement
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Sam Wormley wrote:
| Quote: | Golden Boar wrote:
When people think of [inertial] mass, they think of something they can reach out
and touch, but this idea is wrong. [Inertial] Mass is the resistance of an energy
packet to a change in its spacetime coordinates, or , more simply, [inertial] mass
is resistance to movement.
A photon travels through the vacuum of spacetime at the constand speed
of c, the speed of light. All other particles [with mass] travel through this
vacuum at less than c. This is becuase they have [inertial] mass, or to put it
more correctly, they have a resistance to movement [ie inertia].
Since [inertial] mass is the resistance to movement, this explains why there is no
negative mass.
Can you give a definition of "negative mass"?
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No, as it would make no sense.
| Quote: |
Questions
How do we know that an object at rest has mass if we have never brought
an object to rest?
Photons do not have mass, but they do have momentum. The proper, general
equation to use is E^2 = m^2c^4 + p^2c^2 For the photon, m=0 so E = pc
or p = E/c.
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What has this got to do with an object at rest?
| Quote: |
Recent ideas about the vacuum suggest that it is not empty after all,
but filled with virtual particles, quantum fluctuations, etc. Could
these act like air molecules causing drag, to give rise to an increase
in relative mass?
Inertial mass is believed to be cause by the Higgs field pervading the
cosmos.
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I did not ask about the Higgs field.
| Quote: |
When an object approaches the speed of light, time runs slower for that
object. Does this mean that a photon does not travel through the time
dimension? If so, could it be that travelling through the time
dimension gives an object mass?
Quoting from pgs 391-392, "The Elegant Universe", Brian Greene (1999)
which includes:
"Then, the "speed through spacetime" is the magnitude of the
4-vector u, [((c^2 dt^2 - dx_bar^2)/(dt^2 - c^-2 dx_bar^2))]^0.5,
which is identically the speed of light, c. Now, we can rearrange
the equation c^2 (dt/dtau)^2 - (dx_bar/dtau)^2 = c^2, to be c^2
(dtau/dt)^2 + (dx_bar/dt)^2 = c^2. This shows than an increase in
an object's speed through space, [(dx_bar/dt)^2]^0.5 must be
accompanied by a decrease in dtau/dt, the latter being the object's
speed through time (the rate at which time elapses on its own
clock, dtau, as compared with that on our stationary clock, dt)".
This illustrates an increase in an object's speed through space must
be accompanied by a decrease in dtau/dt, the latter being the
object's speed through time, i.e., time dilation.
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I know that. I stated that in the first sentence of my question.
For some reason, you chose to ignore the questions I asked, and gave
answers to completely different questions. |
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Spaceman
science forum Guru
Joined: 09 Jan 2006
Posts: 1143
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| Posted: Thu Apr 20, 2006 7:01 pm Post subject:
Re: About mass - the resistance to movement
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"Golden Boar" <goldenboar@hotmail.com> wrote in message
news:1145553961.100384.313320@v46g2000cwv.googlegroups.com...
| Quote: | When people think of mass, they think of something they can reach out
and touch, but this idea is wrong. Mass is the resistance of an energy
packet to a change in its spacetime coordinates, or , more simply, mass
is resistance to movement.
A photon travels through the vacuum of spacetime at the constand speed
of c, the speed of light.
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Vacuum of Spacetime?
ROFLOL
Is that like the Hoover of cubicfootseconds!
LOL |
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Old Man
science forum Guru Wannabe
Joined: 04 May 2005
Posts: 101
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| Posted: Thu Apr 20, 2006 7:05 pm Post subject:
Re: About mass - the resistance to movement
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"Golden Boar" <goldenboar@hotmail.com> wrote in message
news:1145553961.100384.313320@v46g2000cwv.googlegroups.com...
| Quote: |
... An object moving through the air will experience drag. As
the speed of the object increases, the drag it experiences will
increase as well.
It is similar with a particle moving through spacetime. As it's
speed is increased, the resistance to movement is also
increased ...
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Erroneous analogy, sloppy language. "resistance" implies energy
loss. In the case of a particle in free space, there is no "resistance
to movement". The energy and momentum of the particle are
conserved. Under acceleration, the particles momentum increases,
but it's mass is invariant.
There is no "résistance" to acceleration, no loss of energy. The
work energy required to accelerate the particle goes to the
relativistic kinetic energy of the particle.
It is true that the particles momentum, p, is not linear WRT to
its velocity, v. For a given change in the particle's momentum,
delta_p, the change in its velocity, delta_v, is such that
delta_v / delta_p => 0 as v => c
No "resistance" involved: as it's inertia increases without limit,
the particle's velocity approaches c.
[Old Man] |
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Golden Boar
science forum Guru
Joined: 17 May 2005
Posts: 651
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| Posted: Thu Apr 20, 2006 7:24 pm Post subject:
Re: About mass - the resistance to movement
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Old Man wrote:
| Quote: | "Golden Boar" <goldenboar@hotmail.com> wrote in message
news:1145553961.100384.313320@v46g2000cwv.googlegroups.com...
... An object moving through the air will experience drag. As
the speed of the object increases, the drag it experiences will
increase as well.
It is similar with a particle moving through spacetime. As it's
speed is increased, the resistance to movement is also
increased ...
Erroneous analogy, sloppy language. "resistance" implies energy
loss. In the case of a particle in free space, there is no "resistance
to movement". The energy and momentum of the particle are
conserved. Under acceleration, the particles momentum increases,
but it's mass is invariant.
|
Mass is resistance to movement. Are saying is that a particle in free
space has no mass? According to special relativity, as the speed of a
particle increases, so does it's mass. Rest mass is said to be
invariant, but has anyone actually brought anthing to rest?
| Quote: |
There is no "résistance" to acceleration, no loss of energy. The
work energy required to accelerate the particle goes to the
relativistic kinetic energy of the particle.
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Yes there is, it is called mass. If there was no resistance to
acceleration, then an object given an initial acceleration would
continue to accelerate indefinitely.
| Quote: |
It is true that the particles momentum, p, is not linear WRT to
its velocity, v. For a given change in the particle's momentum,
delta_p, the change in its velocity, delta_v, is such that
delta_v / delta_p => 0 as v => c
No "resistance" involved: as it's inertia increases without limit,
the particle's velocity approaches c.
[Old Man] |
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hhc314@yahoo.com
science forum addict
Joined: 18 Sep 2005
Posts: 90
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| Posted: Thu Apr 20, 2006 8:44 pm Post subject:
Re: About mass - the resistance to movement
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Golden Boar posted:
" If there was no resistance to
acceleration, then an object given an initial acceleration would
continue to accelerate indefinitely."
What is there about f=ma that you don't seem to grasp?
Harry C. |
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Golden Boar
science forum Guru
Joined: 17 May 2005
Posts: 651
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| Posted: Thu Apr 20, 2006 9:21 pm Post subject:
Re: About mass - the resistance to movement
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hhc314@yahoo.com wrote:
| Quote: | Golden Boar posted:
" If there was no resistance to
acceleration, then an object given an initial acceleration would
continue to accelerate indefinitely."
What is there about f=ma that you don't seem to grasp?
Harry C.
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What do you think that I don't seem to grasp?
F = ma, and therefore a = F / m. It is clear that mass resists
acceleration.
Do you think that massive objects continue to accelerate without an
applied force, and thereby disproving F=ma? |
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PD
science forum Guru
Joined: 03 May 2005
Posts: 4363
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| Posted: Fri Apr 21, 2006 4:05 am Post subject:
Re: About mass - the resistance to movement
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Golden Boar wrote:
| Quote: | When people think of mass, they think of something they can reach out
and touch, but this idea is wrong. Mass is the resistance of an energy
packet to a change in its spacetime coordinates, or , more simply, mass
is resistance to movement.
|
Actually this is not a particularly inclusive definition of mass. For
example, two colliding photons do not have any resistance to movement,
nor do they have invariant mass individually, but together they *do*
have invariant mass, as evidence by the positron-electron pair that
emerges from the collision and bears the same invariant mass.
| Quote: |
A photon travels through the vacuum of spacetime at the constand speed
of c, the speed of light. All other particles travel through this
vacuum at less than c. This is becuase they have mass, or to put it
more correctly, they have a resistance to movement.
Since mass is the resistance to movement, this explains why there is no
negative mass.
|
And actually, invariant mass *can* be negative. It's not compatible
with *your* definition of mass, but as I said, your definition is not
particularly inclusive.
| Quote: |
Relative mass
An object moving through the air will experience drag. As the speed of
the object increases, the drag it experiences will increase as well.
It is similar with a particle moving through spacetime. As it's speed
is increased, the resistance to movement is also increased.
Since a photon's speed is constant, there is no change in its
resistance.
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What resistance does a photon have at all? If it has a finite
"resistance" as you've defined it, then a photon should be capable of
being accelerated, since what you're invoking is the mass as defined by
Newton's 2nd law: F=ma.
| Quote: |
Questions
How do we know that an object at rest has mass if we have never brought
an object to rest?
|
Consider the value of a linear extrapolation.
| Quote: |
Recent ideas about the vacuum suggest that it is not empty after all,
but filled with virtual particles, quantum fluctuations, etc. Could
these act like air molecules causing drag, to give rise to an increase
in relative mass?
When an object approaches the speed of light, time runs slower for that
object.
|
Not sure what you mean by that. Be *very careful* about overly shallow
popularizations of SR here.
| Quote: | Does this mean that a photon does not travel through the time
dimension? If so, could it be that travelling through the time
dimension gives an object mass?
|
PD |
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hhc314@yahoo.com
science forum addict
Joined: 18 Sep 2005
Posts: 90
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| Posted: Fri Apr 21, 2006 1:24 pm Post subject:
Re: About mass - the resistance to movement
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Golden Boar posted:
"What do you think that I don't seem to grasp?"
Well, for starters Physics 101, specifically simple mechanics. You
don't apper understand what the parameters mean, their definitions how
they relate to one another, and that acceleration is the result of an
applied force as has been very patiently explained to you in a
different thread. You certainly don't grasp what "resistance" means, or
that acceleration is simply the time rate of change in velocity. You
don't appear to grasp what a reactive force is, and certainly don't
seem to understand that f=ma is a solution of Newton's f = dp/dt for a
mass invariant special case in classical Newtonian mechanics.
It appears that you choose to us the term "resistance" because you
haven't yet learned about "reactive forces", kinetic energy, statics,
dynamics or just about every other concept that is normally studied
during the first month or two of any introductory physics course taught
at either the highschool or first year undergraduate college level,
including the basic concepts of momentum and energy. You clearly don't
grasp that the application or force to a particle of mass you change
its momentum and energy state. You confuse this with "resistance"
evidently because you fail to grasp the nature of reactive force and
continue to confuse it with a resistive force like friction or
aerodynamic drag.
Someone in another thread carefully explained some of these concepts to
you very clearly, but you went on to blather still more nonsense
without every bothering to try and comprehend what he was telling you.
| Quote: | From my vantage point, this tags you as being just another kook without
any clue whatsover. |
Have a nice day. Harry C. |
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hhc314@yahoo.com
science forum addict
Joined: 18 Sep 2005
Posts: 90
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| Posted: Fri Apr 21, 2006 1:44 pm Post subject:
Re: About mass - the resistance to movement
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Golden Boar continues to blather nonsense:
"When people think of mass, they think of something they can reach out
and touch, but this idea is wrong. Mass is the resistance of an energy
packet to a change in its spacetime coordinates, or , more simply, mass
is resistance to movement."
Sorry guy, but a body of mass in motion will continue to travel at
constant velocity and direction unless a net external force is applied
to it. Velocity is movement. Physics doesn't get any more basic than
this.
If you don't yet understand even the basic concepts of mechanics
(statics and dynamics), what on earth could cause you to believe that
you could understand advanced concepts and speculative theory... Seems
to me that doing so would be equivalent to attempting to read, say
"Tolkien" without yet knowing how to read and what the words mean.!
Harry C. |
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PD
science forum Guru
Joined: 03 May 2005
Posts: 4363
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| Posted: Fri Apr 21, 2006 1:52 pm Post subject:
Re: About mass - the resistance to movement
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Golden Boar wrote:
| Quote: | Old Man wrote:
"Golden Boar" <goldenboar@hotmail.com> wrote in message
news:1145553961.100384.313320@v46g2000cwv.googlegroups.com...
... An object moving through the air will experience drag. As
the speed of the object increases, the drag it experiences will
increase as well.
It is similar with a particle moving through spacetime. As it's
speed is increased, the resistance to movement is also
increased ...
Erroneous analogy, sloppy language. "resistance" implies energy
loss. In the case of a particle in free space, there is no "resistance
to movement". The energy and momentum of the particle are
conserved. Under acceleration, the particles momentum increases,
but it's mass is invariant.
Mass is resistance to movement. Are saying is that a particle in free
space has no mass? According to special relativity, as the speed of a
particle increases, so does it's mass. Rest mass is said to be
invariant, but has anyone actually brought anthing to rest?
There is no "résistance" to acceleration, no loss of energy. The
work energy required to accelerate the particle goes to the
relativistic kinetic energy of the particle.
Yes there is, it is called mass. If there was no resistance to
acceleration, then an object given an initial acceleration would
continue to accelerate indefinitely.
|
That's not what mass does.
The time that an object accelerates is set not by the mass, but by the
time the net force is available. That's what F=ma means. When F stops,
so does a. The mass has nothing to do with it.
What the mass does it is tell you the proportion of acceleration to the
force. E.g. if m = 7, then you will get 1 part acceleration for 7 parts
force applied. If m = 21, then you will get 1/3 part acceleration for 7
parts force applied. That's all it means.
If the force is there indefinitely, then the acceleration will be there
indefinitely. There is a caveat. F=ma is a formula that only works at
low speeds, if m is taken to be the rest mass of an object. There are
two ways to fix this to be more general. The antiquated way is to say
that m increases as the speed increases, so that m is no longer the
rest mass. The better way to fix this is to write the equation as
Newton originally described it: F = dp/dt. Here, p = (gamma)(beta)m*c
for an object of nonzero rest mass. In this form, the law works
perfectly instead of as a low-speed approximation.
Does this help?
PD
| Quote: |
It is true that the particles momentum, p, is not linear WRT to
its velocity, v. For a given change in the particle's momentum,
delta_p, the change in its velocity, delta_v, is such that
delta_v / delta_p => 0 as v => c
No "resistance" involved: as it's inertia increases without limit,
the particle's velocity approaches c.
[Old Man] |
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John Sefton
science forum Guru Wannabe
Joined: 06 May 2005
Posts: 143
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| Posted: Fri Apr 21, 2006 2:03 pm Post subject:
Re: About mass - the resistance to movement
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PD You could not have meant what you said
"For
example, two colliding photons do not have any resistance to movement,
nor do they have invariant mass individually, but together they *do*
have invariant mass, as evidence by the positron-electron pair that
emerges from the collision and bears the same invariant mass".
Photons colliding? Cool!!
John |
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PD
science forum Guru
Joined: 03 May 2005
Posts: 4363
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| Posted: Fri Apr 21, 2006 2:09 pm Post subject:
Re: About mass - the resistance to movement
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ma1ibu wrote:
| Quote: | PD You could not have meant what you said
"For
example, two colliding photons do not have any resistance to movement,
nor do they have invariant mass individually, but together they *do*
have invariant mass, as evidence by the positron-electron pair that
emerges from the collision and bears the same invariant mass".
Photons colliding? Cool!!
|
Yes, indeed. You did not know this happens?
See the Feynman diagrams at
http://l3.web.cern.ch/l3/analysis/gg/ggpicutres.html and the
measurement of these events.
PD |
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Sam Wormley
science forum Guru
Joined: 30 Apr 2005
Posts: 1491
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| Posted: Fri Apr 21, 2006 2:19 pm Post subject:
Re: About mass - the resistance to movement
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ma1ibu wrote:
| Quote: | PD You could not have meant what you said
"For example, two colliding photons do not have any resistance to movement,
nor do they have invariant mass individually, but together they *do*
have invariant mass, as evidence by the positron-electron pair that
emerges from the collision and bears the same invariant mass".
Photons colliding? Cool!!
John
|
John, PD meant what he said and he said what he meant.
http://www.jp-petit.com/science/darkside/a12062.gif
http://homepage.mac.com/stevepur/physics/matter/matter.3.html |
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