Question

The force on a north pole, `vecF = mvecB` , parallel to the field `vecB` . Does it contradict our earlier knowledge that a magnetic field can exert forces only perpendicular to itself?

Answer 1

Yes, it seems to contradict with our earlier knowledge that a magnetic field can exert forces only perpendicular to itself.

`vecF = mvecB`

here ,

 `vecB` = Magnetic field

m = Magnetic charge
For a positive magnetic charge, force is along the magnetic field.
For a negative magnetic charge, force is opposite to the magnetic field.
Thus, it contradicts the notion that a magnetic field can exert forces only perpendicular to itself.