Most active questions
753 questions from the last 30 days
67
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What is "Induced Atmospheric Vibration"?
The blackout seen today on the Iberian Peninsula has been attributed to a "rare" phenomenon known as "induced atmospheric vibration":
It says that "due to extreme temperature ...
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16
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10
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How do we know what's IDEAL if we have never seen it?
Almost everything I learn in high school considers an "Ideal System".
When dealing with classical mechanics, air resistance, friction, and a lot of other cool, unpredictable stuff are being ...
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11
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6
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In light cone, why is it a cone and not a sphere, given that light travels in all directions in space-time? Is it a projection of slice of 4D sphere?
The light cone concept says that whenever a flash of light is tracked from a point in space-time, its path becomes a cone in 3d. The explanation I found is that you stack up the circle that it tracks ...
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8
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14
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How can heat pumps be more efficient than electric/resistive heating?
I cannot understand how a $COP > 1$ does not contradict the laws of thermodynamics (the first one, in particular).
Whatever searches I do, return things like "a heat pump is moving heat, not ...
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12
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7
answers
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Where is potential energy stored in a human body?
Where is potential energy stored in a human body? See, humans need energy to live. Using this energy we can do work, so this is potential energy. When we raise a body to a height $h$, then the ...
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6
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7
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If an object falls without friction in a gravitational field, is the average speed independent of the path taken?
If an object falls without friction in a gravitational field, is the average speed independent of the path taken?
Consider a marble falling $1 \; m$ in a vacuum under the influence of the Earth's ...
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votes
4
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Why didn't Earth bounce upon collision during the formation of moon?
Simulations of moon formation show Earth splashed when a Mars-sized planet collided with it. Why doesn't Earth bounce like a rubber ball? What makes it behave like a liquid? I heard this depends on ...
- 12.9k
12
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3
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What exactly does it mean to be having a wattless current?
I came across this concept of wattless current, in which power factor is zero.
My question is that is this practically possible? For the power factor to be zero, the resistance in the circuit will be ...
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11
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3
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What's the probability distribution of when the ball will fall from Norton's dome?
Suppose our world is completely described by Newtonian mechanics. All the materials are rigid and can be cut infinitesimally.
There exist scenarios where the future is intrinsically probabilistic. ...
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6
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4
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Doubt regarding center of mass of a cone
I would just like to confirm that if I have a solid cone of uniform density and I make a plane cut such that the 2 parts obtained have an equal mass, is it correct to state that the center of mass of ...
15
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4
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967
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Frame dependence of De Broglie wavelength
This might sound a bit silly but the De Broglie wavelength depends on the momentum of the particle which is a frame dependent quantity, so naturally we can say that the corresponding wavelength is ...
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4
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4
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How has the rotation of Earth been accounted for in the theory of gravitational time dilation?
The article A new clock shows how gravity warps time — even over tiny distances states that when two atomic clocks are placed one above the other, the one in the stronger gravitational field (lower) ...
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6
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7
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Why is mechanical energy lost and linear momentum not conserved when a string suddenly becomes taut in a vertical two-mass system?
I came across this puzzling mechanics problem and would appreciate some insight into the physics behind it, especially regarding energy loss and momentum conservation.
Problem Setup:
A massless, ...
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20
votes
2
answers
2k
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Can a high enough charge density alone lead to the formation of a black hole?
Is there a fundamental upper limit to electric charge density?
If not, is it possible to concentrate enough charge in a small region of space such that an electron wouldn't be able to escape unless ...
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10
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4
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Asymptotic integral in Peskin & Schroeder, Problem 6.3
The question is about P&S QFT Problem 6.3. In question (a), the contribution to $a = \frac{g - 2}{2}$ from Higgs boson is calculated, the result is:
$$
\delta a = \frac{\lambda^2}{16 \pi^2} \int_0^...
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