An electron traveling toward the north with speed 4.0 x 10 m/s enters a region where the Earth's magnetic field has the magnitude 5.0 x 10"? T and is dir sted downward at 450 below horizontal. (a) What is the magnitude of the force that the Earth's magnetic field exerts on the electron? (b) What direction the force on the electron, N, S, E, W, Up, or Down? (e = 1.60 x 10 ]' C)