(c) find the magnetic force of an electron moving straight up at 3 x 10^6 m/s in the same magnetic field.

At a certain place, Earth's magnetic field has magnitude 0.050 mT. The field direction is 70.0 below the horizontal; its horizontal component points due north. (a) Find the magnetic force on an oxygen ion (O2 ) moving due east at 250 m/s. (b) Compare the magnitude of the magnetic force with the ion's weight, 5.2 x 10-2 N, and to the electric force on it due to Earth's fair-weather electric field (150 N/C downward)