I have 2 problems with Coulumb's law:(adsbygoogle = window.adsbygoogle || []).push({});

1) contrary to a gravitational field isn't there a limit to the area of a magnetic field? How can this be calculated? F= kq1q2 / d^2 doesn't point it out.

2) same thing moving inward. Does the force grow to infity, when distances get smaller.

Also a related exercise: 2 electrons are moving toward each other at a specific speed (v) and a specific angle (a). What is the minimal distance (l) between them?

They'll move with a hyperbolic trajectory, but in my opinion contact should also be possible (necessity of sufficient speed).

My calculations:

F=kq^2 / l^2 E=mv^2/2 E=Fl*cos a

kq^2 / l^2=mv^2/2l*cos a

l=2kq^2*cos a/mv^2

When using electron's mass, charge and a is 0 (cos a=1) the answer is ruffly l=506/v^2

Of course that rules out the possibility of contact, but the flaw is already in Coulumb's equation.

Does this make any sense?

MarekS

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# Homework Help: Boundaries of Coulumb's law

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