Hi, reading your calculations I came to think:
what is the gravity value at the center of the earth?
In a strange way I would like to think that it is 0 (zero).
Similarly, at the centre of black holes: paradoxical 😱
What are your opinion about?
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That depends on who is explaining them to you, not the 'laws of physics' being unclear or wrong in any way.
I'm not surprised the professor ignored your letter to be honest.. Your confusion seems to be what the differences are between a lamp and human being!
The lamp and the person are not in any way similar.
The lamp is in a state of rest, equilibrium with pretty much all the forces exerted on it in equal and opposite to those inside and between the molecules and atoms.
A living person is not in any way in a state of equilibrium - it has to do a lot of work just in staying up, let alone holding buckets of water.
If you died and had a weight placed on top of your body then you would be in a comparable state to the lamp and you can start comparing the two then.
Even then your body is changing as it decomposes. The weight on your soft tissue is being held up by the water or other fluid pressure in your cells or the tensions and compressions and nuclear forces in the molecules of your bones. As you decompose even these change and it's not until you are completely dust that you can then compare yourself with a street lamp.
You confusion about this seems to be about what a human is. A human - any living creature really - needs a lot of processes, a lot of energy usage ('work' in physics terms) just to overcome the natural state of equilibrium which would be to be dead and flat on the ground...
I think that the laws of physics are the same for humans and material world. If a weight of 5kg must be lifted on the 5th floor the energy required is the same if I use an electric motor pulley or a manual pulley . You do not you agree?
Somewhere else I have to admit that I have not yet understood well the difference between life and death. A man dead from one second what has less than a second before? Materially have everything .......
Mahhh............🙄
Well who is doing the measurements?
If the guy in the first galaxy measures the energy of the signal transmitted and also could measure the signal received somehow using equipment based in his galaxy then the energies would be the same.
Similarly, if the guy in the 2nd galaxy can use his own equipment in his galaxy to measure the transmitted energy and the energy received then they would be the same also.
Similarly, a third observer from outside these two galaxies who is able to see and measure both would also see no difference in energies received and transmitted.
If the guy in the 1st tells the one in the 2nd his measurements then the two will be different as they have been measured in completely different frames of reference.
The energy is still conserved but it has been measured differently by the two people!
I'm afraid that your confusion and questions are only because you haven't studied physics in a great enough depth and the physics books you talk of are too simple. You generally don't learn this stuff until you start university but then it is some of the first and simplest stuff you learn.
I seem to remember my first year degree book has nice pictures of people on trains demonstrating and deriving the Lorentz transformations (how you compare measurements in one frame of reference to another).
As an example of what I mean, imagine a 1kg weight on the floor of a train:
To a passenger on the train, it is completely still and has no kinetic energy. To someone standing on the station's platform as the train goes past at 1 metre a second, the weight has kinetic energy of half a joule. Which is correct? Both are! The measurements in both frames of reference are correct.
Laws of physics don't relate to specific measurements but relate to overall concepts. If that weight is picked up and dropped then the measurements done in both the passenger's world and the platform person's world will both confirm conservation of energy, for example, even though the numbers in their measurements will be different.
Get a good first year degree book like "Fundamentals of Physics" and read through it...
Actually, in a state of dynamic equilibrium.
Dead means detached from the source of an energy that maintains it in dynamic equilibrium. However, if attachment returns back dead cells may regenerate.
Search for NDE.
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AAAAAAAAAGHGHGHGH!
I mean the difference between what a human is and what a lamp is!
A human just to hold himself upright, to breath, to not just drop to the ground requires a LOT of work as our bodies are in no way in a state of equilibrium like the lamp is. Just being alive can feel tiring if we don't eat and sleep enough.
Perhaps the language barrier here is too great to have this conversation?
and your constant change of topic will just become more and more confusing.
To answer the last question, a living person has a self-perpetuating set of processes going on. A dead person has none. The difference in a living and dead person is only these set of processes. It has nothing to do with a change in mass..
Same as a car engine - when it is 'alive', the self-perpetuating motion continues as long as the fuel, air and electricity are supplied. Stop the continuing cycle and, even with the fuel, air and electricity returned, the engine remains 'dead' until this cycle is set in motion again.
To the wrong person, terminology and semantics can just introduce more confusion - especially if two terms use the same words!
Best to leave these out until the ideas are understood first in my opinion.
Dynamic implies movement while static implies stationary. I.e. for dynamic equilibrium constant movement is needed.
Like, in case of your car engine: if it runs, it keeps itself running. If it stall, it is no longer in dynamic equilibrium. It does not need a source of an energy to be stall, but in order to run (to be in the state we call dynamic equilibrium) it burns a fuel.
The same with human beings. But the difference between engines and human beings is manly in levels of activity on which cycles are closed: while everything in engines can be directly measured and observed, some processes in human beings can't be directly measured and observed, since they happen on much fine level than existing tools are made of.
A human being can "hold a lamp" if all joints are held into the proper position, such as with a mummy or in a body cast. The lamp is then "held" in the air by the external rigid frame rather than the exertion of muscles against the skeleton and the lamp. This way, it doesn't matter if the human is dead or alive.
A car with a manual transmission can be at a stop on an incline in two ways. One is to push in the clutch all the way and press on the brake pedal. The brakes keep the car still. Another way is to put the car in gear and let out the clutch enough just to counteract the force of gravity tending to pull the car backwards. One may have to rev up the engine to maintain enough power to do this.
Technically, concerning only the motion of the car itself, neither one of these actions is doing work. But looking more closely (or "looking under the hood" both literally and figuratively), in the second case there is indeed work being done by the engine, and that work is going into wearing out the clutch.
In the same way, a person holding an object still in their hands is not doing any work ON THE OBJECT, but is doing work with their muscles to hold their skeleton and the object in position. Fortunately, muscles don't burn out as fast as clutches do.
Actually, they do burn out faster, but they regenerate constantly. Similarly, some cars can't last long if their organs don't regenerate periodically. 😉
No it is not. The bare number is the same, but I attach a quite different meaning to it. I calculated (correctly) the kinetic energy gained (48 joules) at the end of one second. You then took this to mean a power of 48 watts due to motion downwards, then equated that to the power needed to stay motionless! The average power over the first second is indeed 48 watts, but this disguises an initial power of 0 watts and an instantaneous power at the 1 second point of 96 watts. The power is increasing linearly, as the mass accelerates linearly. To hold it steady takes no power at all!
Your explanation are really good.
But being bad I raise these objections:
If I live on the emitting galaxy, I know exactly the broadcast signal, but I can not know the signal received on the Galaxy 2.
If I live on the receiving galaxy I know exactly what I get, but in contrast, nothing I know of the emitted signal.
These two are severe limits.
If we imagine a kind of hyperspace's phone, we also know of the far away signal, but these being performed on two different referece's systems, it meant to compare them without correlation.
Finally there is another possibility: to be an observer located in the midway between the two and has the ability (and time) to measure the transmitted and the received signal and then make a comparison related.
But this means to reintroduce an absolute space and time and a privileged observer against relativity.
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No it doesn't. It's just another inertial frame with a velocity of -v/2 with respect to one galaxy and +v/2 with respect the other.
I think the answer you are looking for is...
...Who cares about velocity, charged plates and lamp post arms, how about you send me ONE of the bottles, we'll both open them and enjoy a nice glass of wine and call it a day!
...Who cares about velocity, charged plates and lamp post arms, how about you send me ONE of the bottles, we'll both open them and enjoy a nice glass of wine and call it a day!
Unfortunately I don't have a bottle with flatter one side to show that an energy is needed to keep everything (from a bottle to a pole arm) in shape, while gravitation constantly does it's steady work, never being tired...
What is gravitation?
That's completely consistent with what I said. Remember, if they're both moving away from you and you're on a line between them, the sign of V (or V/2) is opposite.
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