Main post link -> https://brilliant.org/assessment/s/mechanics/4583580/
In this particular problem (which I also solved), a solution which has been submitted is completely wrong conceptually. Solution says that centrifugal force is balanced by Lorentz force. Of course in our frame there would be no centrifugal force since our frame is inertial. I objected to that argument by adding comment below the solution itself. I thought that at least person who presented argument would reply or at least Physics master would reply. But nobody is replying there which is surprising for me. People who did not solve this and read this solution may get wrong physical picture and for these people it is important to clarify logical fallacy of the argument. Would Physics master please take note of it??