Q vxB Magnetic Force: Reconciling Two Situations

[eltodesukane]

there is something I don't understand
maybe someone can tell me

- a charge q has velocity v along the x axis
- there is a uniform magnetic field B along the y axis
- so the particule experience a force F=qvB along the z axis

Now consider the same situation in a reference frame moving at velocity v along the x axis.
Now F=qvB=0 and there is no force on the particule.

What am I missing?
How to reconcile those situation?

 

[Simon Bridge]

The classical magnetic force depends on the reference frame - this is correct.
You have found a place where the theory you have been taught is incomplete.

To resolve this, we need special relativity.

http://www.pa.msu.edu/courses/2000fall/PHY232/lectures/magforces/frames.html
http://galileo.phys.virginia.edu/classes/252/rel_el_mag.html