Questions tagged [reference-frames]
A reference frame is a particular coordinate system chosen to represent physical entities. The notion is most often used in special and general relativity to denote particular coordinates chosen on the spacetime manifold.
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Why is the Coriolis force "pseudo" but the dropped ball's path isn't?
In the classic Moving Train example:
Inside a moving train, a passenger throws a ball straight up. To the passenger, the ball appears to move in 1D (straight up and down). However, to an observer ...
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Constant acceleration in space
I am not a physics student or expert and it's been over 4 decades since I studied any physics, so this may be a very stupid question for this group, but we are trying to figure this out for the ...
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What does it mean when physicists say: "An object rotates around any point you choose"?
I say that the Earth rotates around its center of mass (CoM), but physicists tell me "Earth rotates around any point you choose".
I do not understand how an object’s rotation can be ...
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Does the electric field of a parallel-plate capacitor change as it accelerates?
Assume that the two plates of an infinitely large parallel-plate capacitor accelerate along the field lines simultaneously in the lab frame. (Fringing effects are excluded.) Is the uniform electric ...
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Understanding Coriolis acceleration for high school students without calculus
I watched the video Derivation of Coriolis Acceleration, which shows how Coriolis acceleration is derived. However, I have difficulty understanding some parts of the derivation, especially:
How the ...
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Objects moving at almost the speed of light [duplicate]
I’ve been curious:
With Einstein s theory of relativity, as an object moves almost at the speed of light, time for it gets slower as compared to a person standing still. If you reach almost the speed ...
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Why must the center of pressure lie behind the center of mass in a rocket?
I understand the concepts of both CP and CG however I am struggling to tie the two together in this context. I also aware that they are linked to stability of the body but how, mathematically and ...
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2 ways of resolution of vectors
I am learning mechanics in high school and while doing wedge and related problems where you have to resolve the forces, every time we split it into $F\sinθ$ and $F\cosθ$ (considering force is $F$), ...
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Does the "naturality" of Generalized Coordinates Depend on Reference Frame?
I'm studying Classical Mechanics at the upper-undergraduate level, and we're currently learning Hamiltonian Mechanics. From what I understand, the Hamiltonian is the total energy when:
"The ...
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What is the Sun's obliquity to the invariable plane?
I'm trying to figure out the obliquity (rotation axis of a body) of the Sun but relative to the invariable plane of our solar system (which is primarily dominated by Jupiter, not Earth).
Various ...
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Application of Reichenbach synchronisation
Suppose I adopt the Reichenbach synchronisation process so that light heading radially away from me- according to my clocks- travels with infinite speed, while light heading directly towards me ...
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How does the concept of "coordinates" makes sense when considering large scales of the universe?
I will describe two instances, that led me to ask the question of relevancy or meaningfulness of coordinates when we are not local in our observation of the universe, but rather we consider a large ...
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Proof and meaning of $\vec{v} = \vec{\omega}\times\vec{r}$
Elementary question but I'm slightly confused about the statement $$\vec{v} = \vec{\omega}\times\vec{r}.$$ I know that $\vec{\omega}$ is simply the time derivative of $\theta$, which, to make things ...
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Has someone ever obtained a relative trajectory being exactly the Coriolis formula without a background centripetal force (as gravity)?
In geophysics and many other cases, the Coriolis formula is clearly linked to a background centripetal force.
Read Anders Persson (UK MetOffice, EU ECMWF, Sweden SMHI, Uppsala) https://scholar.google....
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Do blueshifted and redshifted light sources have differing energies?
The thought experiment:
Two spaceships are passing each other some distance from a star. Both ships are at relativistic speed, one toward and one away from the star. Should the total energy observed ...
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