Everything posted by Genady
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Wolfram Physics Project
What is a justification of identifying the graph distance with a spatial distance? Is it a postulate of the model?
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Wolfram Physics Project
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Did Trump Steal the 2024 Election?
Here is some: Claims in 'Duty to Warn' Letter to Harris Alleging Compromised Election Are Misleading | Snopes.com
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Entanglement (split from Using entanglement to achieve...)
Misconceptions.
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Entanglement (split from Using entanglement to achieve...)
They are entangled.
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Force on the rocket in the rocket problem
@dqqd, this analysis in Wikipedia is quite clear: Variable-mass system - Wikipedia
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Force on the rocket in the rocket problem
I disagree: the force has not been redefined. In the formula \(F=\frac {dP}{dt}\), \(P\) is the momentum of the entire system. If the system is composed of parts, \(P=P_1+P_2+...\), then \(F=\frac {d(P_1+P_2+...)}{dt}=m_1 \frac {dv_1}{dt}+v_1 \frac {dm_1}{dt}+m_2 \frac {dv_2}{dt}+v_2 \frac {dm_2}{dt}+...\), where no mass crosses the boundary of the composed system.
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Force on the rocket in the rocket problem
Force, however, does not depend on the inertial frame you choose.
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Early Morning Club
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Force on the rocket in the rocket problem
But in the OP, v is not "the velocity of the ejected mass relative to the bulk mass," but rather (my emphasis), It depends on reference frame.
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Force on the rocket in the rocket problem
There is no rocket in my scenario. My scenario demonstrates that by applying the quoted formula wrongly, we get a ridiculous result that a force on the bucket is proportional to velocity with which an observer runs by it.
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Force on the rocket in the rocket problem
Remove the bucket and consider a ball of water in free fall. The molecules leave in all directions. The total force on the ball is zero.
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Force on the rocket in the rocket problem
Consider a bucket of water with mass \(m\) and the water evaporating at rate \(\frac {dm}{dt}\). No force is applied to the bucket. Consider now the same bucket in a reference frame where it moves with velocity \(v\). If we apply the formula "F=dp/dt=mdv/dt+vdm/dt" in this reference frame, we get a ridiculous result that there is a force \(F=v \frac {dm}{dt}\) on the bucket. Conclusion: this is a wrong way to apply the above formula.
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Dark Energy May Not Be A Constant Force
Local inhomogeneities and anisotropies do not matter on cosmological scales. The cosmological principle's assumption is that on some large scale, currently about 100+ Mpc AFAIK, the universe is homogeneous and isotropic. All manifestations of the DE so far are on such scales.
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Dark Energy May Not Be A Constant Force
If it does, the cosmological principle needs to be reconsidered.
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no free will = no reason to feel guilty
That is perhaps what he did and now tries to convince himself that he should stop feeling guilty. In his own words,
- Early Morning Club
- Early Morning Club
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prime dilemma
They cannot land as anything else just by the fact that they are primes.
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Choosing how you will die
That will be good. I don't want to die young, healthy, and/or dirty.
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Prime generating polynomial
Yes! +1.
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Is foundational physics stuck?
I disagree. Computational methods are math by itself which are applied to math of the physical theories. E.g., FEM.
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Is foundational physics stuck?
In fact, simulations are MORE math. Given equations that cannot be solved exactly, developing a working method for solving them numerically is a nontrivial math itself.
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Prime generating polynomial
If I'm not mistaken, there is an error in the last part:
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Coral news
Scientists discover the world’s largest coral — so big it can be seen from space | CNN This is cool, but the following video in the story made me, a retired SCUBA instructor, cringe. SCUBA divers / marine biologists, do you see what is wrong with this picture? https://media.cnn.com/api/v1/loops/stellar/prod/video-world-s-largest-coral-4.mp4?c=original