An Electron Traveling Toward the Magnetic North with Speed $400 \mathrm {~km} / \mathrm { s }$

An electron traveling toward the magnetic north with speed $400 \mathrm {~km} / \mathrm { s }$ enters a region where the earth's magnetic field has the magnitude $5.0 \times 10 ^ { - 5 } \mathrm {~T}$ and is directed downward at $45 ^ { \circ }$ below horizontal. What magnitude magnetic force acts on the electron? $\left( e = 1.60 \times 10 ^ { - 19 } \mathrm { C } \right)$