Questions tagged [density]
Density is defined as the mass per unit volume of a substance.
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Alternate statement for Liouville's theorem: Can you say that the relative velocity between any two representative points is zero?
So Liouville's theorem basically says the local density of representative points stays constant or that the flow of representative points resembles that of an incompressible fluid. Can you then say ...
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Is it possible to deduce the density distribution only from the gravity field around it?
Is it possible to deduce the density distribution only from the gravity field around it? Apparently this cannot be done in Newtonian gravity or static cases of GR: in spherical symmetric cases of ...
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How do I calculate the maximum possible atmospheric density/ surface pressure a planet can have?
I'm not entirely sure if this is the right stack but here goes.
I'm trying to design a fictional planet that has less gravity than Earth but I would like to give it an atmosphere as or even more dense ...
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Special theory of relativity paradox (buoyancy)
We have a submarine (sub) in a frictionless liquid and the average sub density is equal to the density of a liquid. Sub is fully submerged not touching the bottom.
Now the sub moves at near speed of ...
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Non-Newtonian Fluid Density
When a projectile hits a non-Newtonian fluid, does the density of the fluid at the spot of impact increase?
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Why does Earth have the largest mean density of all the planets in the solar system?
Browsing the density of the planets (and Pluto, Ceres, Sun and Moon) in the solar system, I observe that Earth is the one with the largest mean density: $5494 \ kg/m^3$. Is there a physical reason for ...
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Does low air pressure or low air density cause altitude sickness?
People usually say that "low air pressure (or more precisely, low partial pressure of oxygen) causes altitude sickness." But air pressure and air density both decrease roughly proportionally ...
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Few doubts in Tensor Densities (Levi-Civita Tensor) section of Adler, Bazin, Schiffer General Relativity book
I am reding Introduction to General Relativity Book by Maurice Bazin, Menahem Max Schiffer, and Ronald Adler.
1st page
$$
\Im_{\alpha \beta}^\gamma=T_{\alpha \beta}^\gamma \sqrt{-g}
$$
is a tensor ...
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How precisely does the density of an object need to match the density of water to achieve neutral buoyancy?
The classic explanation I can find online is that something is neutrally buoyant when its density equals that of the fluid it sits in. For something like a boat, it can sink and increase its submerged ...
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Including laser linewidth in the master equation
Suppose I have a modified Jaynes-Cummings hamiltonian $H_S$ with two cavity modes. I have derived the master equation for this system including decay of both cavity modes: $$\dot{\rho} = -i/\hbar [H_S,...
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Why is the equation $P=ρgh$ valid even when there is a body submersed in the liquid? [duplicate]
The typical proof of $\Delta P=ρgh$ for a liquid is by taking a cylindrical element of it having height $dh$ and cross sectional area $dS$ at depth $h$. For the element to be in mechanical equilibrium,...
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What is density and flow of a fluid in general theory?
Picture below is from Dirac's general theory of relativity. I want to understand the red line.
The author use:
$t=x^0, x=x^1, y=x^2, z=x^3$
$\surd = \sqrt{-g}$
I treat the fluid as analogue of ...
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How is flowrate affected with pressure drop? [closed]
Assume $50\text{ gpm}$ at inlet of a pipe with pressure drop as $10\text{ psig}$. Will the flow at outlet still be same $(50 \text{ gpm})$?
Will a larger pressure drop will decrease the flow rate at ...
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Air carrying almost 2 kg of lead per liter of air through water
The other day some divers and I were doing an experiment under water: attaching lead to a plastic bag that (based on print on the bag) can contain 10 liter of something, blowing air into the bag and ...
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How to do physics on non-orientable surfaces?
Non-orientable surfaces don't have a volume form on it. How do you define the action principle without a volume form? I know somehow string theory is routinely done on non-orientable surfaces but I ...
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