- #1
nonequilibrium
- 1,439
- 2
Ouch, had just written a big post when my university internet connection timed out on posting, so I'll keep this one short but powerful:
I came to the understanding E and B fields are modified when changing reference frames. But what about the following situation:
Charge q (named 1) is fixed, charge q (named 2) is moving with uniform velocity v. 1 exerts an electrical force on 2, and 2 does the same on 1, but the electrical forces are different due to relativistic modifications (and the magnetic field generated by 2 does not affect 1, being fixed).
What does Newton's 3rd law say about this?
Even more so: switch reference frames (keep 2 fixed) and now the forces are switched, meaning it also ignores the principle of relativity.
Surely I must have ignored something elementary (and possibly obvious). Am I right in assuming Lorentz Force gives the effective force? (as E and B are defined that way...) Maybe I have to account for Faraday's Law, but then again, I'm not sure if that is already included in the modificated E-field.
Curious as to what the answer may be,
mr. vodka
NB: As a side, I'm interested in finding out where the statement "charge is invariant" comes from. If there is no theoretical reason for this and purely an experimental one: how can it be experimentally deduced? My problem is that q is defined in terms of E, and we say E is variant, so how do you know maybe q is variant, but we put all the variance in the E-factor? (of course I'm not implying all physicists are wrong and I'm right, I'm just trying to grasp (and thus ask) how we can know it)
I came to the understanding E and B fields are modified when changing reference frames. But what about the following situation:
Charge q (named 1) is fixed, charge q (named 2) is moving with uniform velocity v. 1 exerts an electrical force on 2, and 2 does the same on 1, but the electrical forces are different due to relativistic modifications (and the magnetic field generated by 2 does not affect 1, being fixed).
What does Newton's 3rd law say about this?
Even more so: switch reference frames (keep 2 fixed) and now the forces are switched, meaning it also ignores the principle of relativity.
Surely I must have ignored something elementary (and possibly obvious). Am I right in assuming Lorentz Force gives the effective force? (as E and B are defined that way...) Maybe I have to account for Faraday's Law, but then again, I'm not sure if that is already included in the modificated E-field.
Curious as to what the answer may be,
mr. vodka
NB: As a side, I'm interested in finding out where the statement "charge is invariant" comes from. If there is no theoretical reason for this and purely an experimental one: how can it be experimentally deduced? My problem is that q is defined in terms of E, and we say E is variant, so how do you know maybe q is variant, but we put all the variance in the E-factor? (of course I'm not implying all physicists are wrong and I'm right, I'm just trying to grasp (and thus ask) how we can know it)