Question

Near the equator, the Earth's magnetic field points almost horizontally to the north and has magnitude B=.5 x 10^-4T. What should be the magnitude and direction of the velocity of an electron if its weight is to be exactly balanced by the magnetic force?

Answer 1

FBD of electron at equator -


Lorentz Force = q (v x B)

I think you can do the rest.
Try to comprehend how I decided the direction of velocity vector.