# All Questions

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### Am I just some energy traveled at light speed?

I don't quite understand E=mc² very well, and here is my question: does this equation mean masses are just condensed energy? And does this mean that the extra energy an object has when traveling at ...
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### Can you deduce absolute motion through magnetism?

Trying to understand magnetism I stumble into this example: Suppose there are two electrons travelling side by side in deep space (say, between Mars and Jupiter) at 1 cm distance at .99 c. In this ...
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### Can pressure be subtracted from pressure gradient

I just want to know if the pressure can be subtracted from pressure gradient. I did a google search and it didn't help me. I know the question is silly and the answer to it should be no but at one ...
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### Feynman Diagram of $\nu_\mu + p \rightarrow \nu_\mu + p + \pi^0$

According to my class notes, the following interaction is possible $$\nu_\mu + p \rightarrow \nu_\mu + p + \pi^0$$ I tried drawing a Feynman diagram and got the below, but don't know what happens ...
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### How electromagnetic waves carry energy?

Its said that electromagnetic waves carry energy. Is this because these waves are made up of electric and magnetic field which can cause changes to the stuff that falls with in their range ? That is ...
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### Einsteins theory of relativity and formula of kinetic energy

After seeing both Einsteins theory of relativity [E=mc2] and the formula of kinetic energy [K.E=mv2] I noticed that that they are mostly the same, with the only difference that Einsteins theory uses a ...
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### The true dimension of Dirac field

In natural units with $\hbar=1$ and $c=1$, as we know, the energy dimension of the Dirac field $\psi(x)$ in QED is $\frac{3}{2}$. But in cgs units, what is the true dimension of the Dirac field ...
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### Springs and Cantilevers - how linear and repeatable are they under deformation?

I know you guys only deal with the ideal, but in practice how linear and repeatable is the response of a spring or cantilever when deformed under a test mass?
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### Horizontal and vertical acceleration of a ball on a slope?

I understand that you resolve the components of the balls weight parallel and perpendicular to the slope in order to calculate the force due to gravity that actually acts down the slope. The ...
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### Why do we use a vector space for gluons?

One gluon state cannot be added to another since qcd heavily violates superposition. Why do we still use vector spaces to describe them?
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### why is it so successful to start of with a pair potential before quantizing

As soon as we use the quantum theory all orders of correlation functions start to appear if we move from one scale to another. Why was it so successful to start of with a simple pair potential in the ...
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### Why quantum computer is so fast factoring numbers?

I am trying to get myself a more clear understanding of the root of significant acceleration in number factoring by P. Shor's algorithm. I am probably missing something but q-bits for me are no more ...
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### Diffraction wavelength relationship

This question appears somewhat similar to other questions asking about why wavelength affects diffraction (a concept which I'm still not 100% sure on...) however my query is different and not answered ...
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### Photon absorption in a medium - basic principle?

I am trying to understand the basic physics of photon absorption in a medium. Take the example of oxygenated hemoglobin (red curve). Clearly at different frequencies/energies relatively more or less ...
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### Difference between $E$ field configuration, sheet of charge: infinite sheet of charge, conducting vs. non-conducting

This is a very easy question, but I often confused myself. Perhaps someone could explain this concept again: A non-conducting infinite sheet of charge has the electric field configuration ...
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### Transforming to a rotating frame in the x-basis

This is given as the equation obtained after transforming to the rotating frame in the x-basis. I know that the general form of the rotation operator for the spin system is given by:  D(\hat ...
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### Calculate Temperature change in a solid due to inductance heating

Trying to calculate temperature increase in a solid due to a current flow, is this along the right lines? First I have calculated resistance due to resistivity, then calculated power from the given ...
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### Gravitational collapse (conservation of energy)

During gravitational collapse, gravitational potential energy of the gas is converted to its internal kinetic energy so the internal energy of the clous of gas is said to be increased But isn't ...
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### Water Moving Through Coffee Grinds

Like many of my peers, I rely on coffee as if it were prescribed to me. It might even be classified as an addiction if it weren't for the cultural norms surrounding a cup of coffee or tea in the ...