1)In a physics lab a positive charge of 20nC is moved horizontally with a velocity of 10m/s due west. The magnetic field of the earth at this location is parallel to ground and from north to south. Calculate the force on the charge. 2) the forumla could be : F = qvBsinθ = qv⊥B .. but i dont know how to calculate this, could you pls help me ? I am really not good physics student..