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• Users: mairzydoats
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1. ### I Gravity on Einstein's train

https://www.physicsforums.com/threads/need-help-understanding-electromagnetics-and-relativity.835867/ post #2: "Increasing the momentum in the y direction while keeping the momentum in the x direction fixed will actually decrease the velocity in the x direction"
2. ### I Gravity on Einstein's train

... and another question: Wouldn't it actually require a y-directed force just to keep this train moving at v in the y-direction? I ask because if the accelerating rocket's floor were the only force acting on the train, then in order for the train to conserve its momentum in the y-direction as...
3. ### I Gravity on Einstein's train

Hello A couple of questions. Would a marble placed on the floor of the train roll towards the back? Would a string attached to a penduluum-like mass hung from the ceiling of the train make an acute angle facing the rear wall, and an obtuse angle facing the front wall, rather than hang...
4. ### Need help understanding electromagnetics and relativity

Thank you, vanhees
5. ### Need help understanding electromagnetics and relativity

Thanks Ben No real academic or professional background in either. But what I do know today, I've learned mostly on my own, having become fascinated with electromagnetic theory. Some years back I read a textbook on electromagnetics by an author/physicist named Nannapaneni Narayana Rao called...
6. ### Need help understanding electromagnetics and relativity

Thanks so much, everybody! I'm wondering if there are any tutorials out there on understanding some of the mathematical language that has been used throughout this thread involving matrices, tensors and suchlike to describe vectors, because I'm sure I'd find it helpful. I know I'm missing out...
7. ### Need help understanding electromagnetics and relativity

Okay. So in K, its velocity in the x-direction is not constant, as my non-relativistic model led me to incorrectly conclude, but actually decreases. And I'm guessing, this is having something to do with the mass increase of the particle as its acceleration in the y-direction increases its...
8. ### Need help understanding electromagnetics and relativity

Hello I'm having a little trouble understanding how two observers in two different inertial frames of reference would view the same simple electromagnetic event. Let's call the first frame K, and we can use cartesian coordinates x, y, z, and t for time in K. There is an electric field E in K...
9. ### Relativistic transformation of the Lorentz force (E + v x B)

oh wait a minute ... [duhh] ... time still dilates. ha-ha. I guess a clock moving with my test charge would tick less than a clock situated on one of the plates as the charge is accelerated in the positive z direction by either E or E'. I still really have to mull this over & study before I'm...
10. ### Relativistic transformation of the Lorentz force (E + v x B)

but the force in my question is created by an E field whose only component is in the positive z-direction, and this, along with any acceleration it may create, is also in the positive z-direction. The transformation of these frames parallel to the x-y plane the test charge moves in doesn't...
11. ### Relativistic transformation of the Lorentz force (E + v x B)

Thank you for your reply. I apologize if my understanding of the subject matter is not advanced enough for me to know what you mean. How can the force on something, which is a 'real event', change simply because change our inertial frame of obervation?
12. ### Relativistic transformation of the Lorentz force (E + v x B)

Here is a problem: Imagine two equally charged capacitor plates parallel to the x-y axis, whose area is large enough compared to the distance between them that fringe effects can be ignored. The bottom plate (at z=0) is + charged, and the top is - charged. The vector field E is therefore...