# All Questions

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### What else does the fabric of space-time do?

I know that, the fabric of space is bended so there is a path for another planet to follow to cause gravity I.E. the sun and the earth ( i think) Is htere any othe rthing's the fabric of space-time ...
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### Range of electromagnetic waves

I was reading this article. There is a statement "It is a well-known fact that the telecom towers mounted with antennas in the lower frequency bands can cover far greater areas than those using the ...
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### Reference for the predictability of rigid body dynamics

I'm looking for a reference, journal article, paper, etc. that supports the idea that classical mechanics, in particular rigid body dynamics, is largely predictable. A view coming from the background ...
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### Rotating sphere and circular trajectory: minimum speed

I have a sphere (mass = 3 kg), constrained to a fixed length rope, rotating (radius = 5 m) on a vertical plane. My textbook ask me about the minimum speed in the highest point in order to keep the ...
I was reviewing the first few chapters of Weinberg Vol I and found a hole in my understanding in page 112, where he tried to show in the asymptotic past $t=−∞$, the in states coincide with a free ...
I need to know the mathematical argument that how the relation is true $(C^{-1})^T\gamma ^ \mu C^T = - \gamma ^{\mu T}$ . Where $C$ is defined by $U=C \gamma^0$ ; $U$= non singular matrix , $T$= ...