Sagittarius A-Star's latest activity
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I remember looking at relativistic hoops and disks a long time ago, but I no longer recall most of the details. I do recall Greg Egan... -
So, if you do just treat the rim as one dimensional, with a linear mass distribution per the COM frame, you do get KE unbounded in the...
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Sagittarius A-Star replied to the thread Undergrad KE of rotating disc.The proper area in the non-Euclidean geometry doubles close to the speed of light: ##A(R)= 2\pi \int_0^R \gamma r \, dr= {2 \pi c^2...
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Sagittarius A-Star replied to the thread Undergrad KE of rotating disc.The rest-mass depends on ##\omega## because of internal stress.
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Sagittarius A-Star replied to the thread Undergrad Why is the Lorentz Force always perpendicular to velocity?.Purcell discussed also a scenario, in which, in the lab-frame, the object moves only vertically towards the horizontal conductor. Also...
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Sagittarius A-Star reacted to Demystifier's post in the thread Undergrad Why is the Lorentz Force always perpendicular to velocity? with
Informative.
Not really the answer to the OP's question, but an interesting observation. Assuming that the mass squared $$m^2=p^{\mu}p_{\mu}$$ does... -
Sagittarius A-Star replied to the thread Undergrad Why is the Lorentz Force always perpendicular to velocity?.I agree, and your calculation-result is equivalent to that of Purcell. I think that Purcell's book addresses students, who did not...
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Sagittarius A-Star reacted to pervect's post in the thread Undergrad Why is the Lorentz Force always perpendicular to velocity? with
Like.
I'm trying to untangle the notation. I am assuming that the lab frame, S, is unprimed, so all unprimed quantites are measured in S... -
Sagittarius A-Star reacted to pervect's post in the thread Undergrad Why is the Lorentz Force always perpendicular to velocity? with Like.
I went over the calculation from Purcell from the references that others have posted - thanks to all who responded, by the way - and I...
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Sagittarius A-Star replied to the thread Undergrad Why is the Lorentz Force always perpendicular to velocity?.The effect of this on the charge line density might be an artifact of the constraint in the OP and in the linked simplified calculation...
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Sagittarius A-Star replied to the thread Undergrad Why is the Lorentz Force always perpendicular to velocity?.I think the point is, that for the charge line-density, the quadratic term in ##\beta'## is the first nonzero term. The constant terms...
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Sagittarius A-Star replied to the thread Undergrad Why is the Lorentz Force always perpendicular to velocity?.The simplified calculation, I linked to in posting #42, does an approximation for small ##v## in equation (1). But of course, the...
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Sagittarius A-Star reacted to A.T.'s post in the thread Undergrad Why is the Lorentz Force always perpendicular to velocity? with Like.
Isn't the explanation simply that even a second order term can be relevant if it has a large enough constant factor? You should...
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Sagittarius A-Star replied to the thread Undergrad Why is the Lorentz Force always perpendicular to velocity?.I think that cannot be, because Purcell does a calculation of the electric force in the rest frame of the object via lenght contraction...
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Sagittarius A-Star replied to the thread Undergrad Why is the Lorentz Force always perpendicular to velocity?.At @PeterDonis wrote in posting #4, the Lorentz force is ##F = q \left( \vec{E} + \vec{v} \times \vec{B} \right)##. If there is no...
