Pure maths, physics, logic (braingames.ru): non-trade-related brain games - page 145

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DmitriyN:

Don't worry, we'll open it up, we'll open it up so badly :))

Why don't you drive?)))
 
Drowned the subject. Question for physicists and philosophers: What is the electrical resistivity of a conductor if there is no current flowing through it?
 
DmitriyN:
Drowned the subject. Question for physicists and philosophers: What is the electrical resistivity of a conductor if there is no current flowing through it?
Huh, did they de-energize you? ))
 
DmitriyN: Drowned the subject. Question for physicists and philosophers: what is the electrical resistivity of a conductor if there is no current flowing through it?
It is a constant, independent of the current flowing. At least if it is just a conductor.
 
Mathemat:
It is a constant, independent of the current flowing. At least if it is just a conductor.

What is interesting: it is not possible to prove this, because in order to measure this constant, an electric current must be passed through the conductor. Theoretically, we can assume that any conductor is to some extent a semiconductor, then it turns out there is a dependence. If resistivity depends on at least something (e.g. temperature, and it does depend on it), then it means that everything else does as well, since all quantities are interrelated.

===

And here the question arises: can the current in a conductor be equal to zero at all? It turns out that it cannot.

 
DmitriyN: What's interesting: it is not possible to prove this, because in order to measure this constant, an electric current must be passed through the conductor. Theoretically, we can assume that any conductor is to some extent a semiconductor

A semiconductor is fundamentally different from a conductor.

This constant (and Ohm's law itself, roughly speaking) will depend on whether we consider the material itself to be a conductor, a semiconductor or a dielectric.

 

So, what's the holdup? Don't get too comfortable!

Megamozg is in a boat in the middle of a circular lake of radius R. On the shore is a goblin, eager to eat Megamozg. Fortunately, the goblin can only move along the shore. Unfortunately, its speed is 4 times the speed of Megamozg's boat. All Megamozg has to do to escape is get to shore without getting caught by the goblin.

Can he do it? If so, how?

 
in a spiral?
 
sergeev:

in a spiral?
Well, you've got to prove it. It's a one-time effort .... :)
 
sergeev:
in a spiral?
At first. Up to a certain point.
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