# All Questions

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### How much energy from underwater explosion can become tsunami?

As the title suggests: what is the energy efficiency of generating gravity waves through an underwater explosion? How do the various parameters (depth of detonation, depth of water, gross energy of ...
• 117
2 votes
1 answer
30 views

### Utility of Burger's equation in the study of shock waves

Consider the viscous Burger's equation, $$\frac{\partial u}{\partial t}+u \frac{\partial u}{\partial x}-\nu \frac{\partial^{2} u}{\partial x^{2}}=0, \tag{1}$$ with $\nu>0$ the kinematic viscosity....
• 888
2 votes
1 answer
141 views

• 11
0 votes
1 answer
35 views

### Energy and pressure relationship for cosmic rays [closed]

How to prove $E = 3P$ for cosmic rays? In other words $\gamma = \tfrac43$ for cosmic rays. Whereas for $\gamma=\tfrac53$ we have $E = \tfrac32 P$.
-7 votes
0 answers
51 views

### Why not study quantum mechanics rather than waste time on relativity? [closed]

Relativity is a dubious tweak to Newtonian Gravity why study it?
23 votes
6 answers
3k views

### Is it correct to say that it is theoretically impossible for perfect rigid bodies to exist?

If perfect rigid bodies were to exist, then consider a scenario in which two rigid bodies of equal masses moving with velocities of equal magnitude but opposite in direction colliding against one ...
• 398
0 votes
0 answers
10 views

### Static Equilibrium in fluids and calculating pressure in a moving fluid

Can the below figure support a static state? I presume that is what the question wanted but intuitively the fluid in the diagonal would want to go down and raise the level of the right arm. Am I ...
• 95
-3 votes
0 answers
14 views

### How to deduce the Schrödinger equation by assuming a one-dimensional finite potential well? [closed]

I know the deduction of the Schrödinger equation by assuming a one-dimensional infinite potential well but I can't find the one-dimensional finite potential well.
2 votes
3 answers
925 views

### Do electrons have inertia?

I don't know quantum mechanics and know a little bit about mechanics and a very little bit about subatomic particles but I am just a curious to know the answer to my question. My question is if '...
0 votes
0 answers
20 views

• 154
0 votes
2 answers
48 views

### Angular Momentum about a Point

I am confused by two different definitions of the angular momentum of a particle P about a moving point Q, with point O as the origin of the inertial frame. I learned the first definition from my ...
• 31
0 votes
0 answers
10 views

### Transformation of density with finite deformations

Initially, there is a infinite continuous medium with a given mass density $\rho(\vec r)$, which is a smooth function that vanishes outside of a sphere of radius R. Then, a deformation of medium is ...
0 votes
0 answers
15 views

### How to predict the time domain of pulse from an amplitude mask in frequency domain?

I am studying ultrafast spectroscopy (pump-probe) and I know that ultrashort laser pulses are used for the pump and probe. These pulses often contain multiple frequencies (i.e. polychromatic pulse) ...
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0 answers
27 views

### Most efficient method to evaporate a metal in a vacuum?

If one had a metal block (lets say tantalum) in a vacuum chamber, what would be the most efficient way of evaporating it in regards to the proportion of the input energy directly going into removing ...
1 vote
2 answers
34 views

### What is the current density of a circular current?

Lets consider a wire loop in the $xy$-plane of radius $R$ which carries a current $I$. I want to find the current density $\vec{j}(x)$ of that configuration expressed with delta functions. Intuitively,...
• 13
0 votes
0 answers
10 views

### The cavity method of Ising model in infinity dimension and dynamical mean field

In the article "Dynamical mean-field theory of strongly correlated fermion systems and the limit of infinite dimensions" chapter III.A, when discussing the cavity method of Ising model, the ...
-5 votes
2 answers
85 views

### What would be the value of $c$ where $c$ is the speed of light?

From the equation of $E=mc^2$, where $E$ is the energy, $m$ is the mass and $c$ is the speed of light, so from that we can get $c=\sqrt{Em}$, again from the equation of $\lambda=v/f$, where $\lambda$ ...
0 votes
1 answer
32 views

### How would the vacuum look like if no mass/energy is present in it?

The observable universe is thought to inflate faster and faster towards infinity. The energy will be diluted to zero in the far future. The influence of attractive gravity is getting smaller and ...
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