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HNQ
6:56 AM
1
Q: Is it inertia that a rotating object will rotate forever without external force?

enbin zhengSomeone told me that this is not inertia, but I think it is inertia, because it will rotate forever. In my understanding, inertia is the constant motion of an object without external force. Am I wrong?

 
 
7 hours later…
HNQ
1:55 PM
2
Q: Why electric potential 0 between 2 charges?

John Hon Say we have 2 charges set up like above. Why is $V_3=0$ ? I can understand mathematically that the scalars fields cancel out, but I don't understand it physically. If I place a positive charge in between the 2 charges, it has electric potential energy because it is feels a force towards the n...

 
 
7 hours later…
HNQ
8:53 PM
6
Q: Paradox in the definition of the electric field

AstroRPThe electric field $\bf{E}$ represents how much force would act on a particle at a certain position per unit charge. However, if we actually place a particle in that position, the electric field will have a singularity there (because of the $\frac{1}{r^2}$ in Coulomb's law). Isn't this kind of a...

 

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