$$t=0, \text { an electron with kinetic energy } 12$$ $$
\begin{array}{l}{\text { moves through } x=0 \text { in the positive direction of an } x \text { axis that is }} \\ {\text { parallel to the horizontal component of Earth's magnetic field } \vec{B}} \\ {\text { The field's vertical component is downward and has magnitude }}\end{array}$$
$$\begin{array}{l}{55.0 \mu \mathrm{T} \text { (a) What is the magnitude of the electron's acceleration }} \\ {\text { due to } \vec{B} ? \text { (b) What is the electron's distance from the } x \text { axis when }} \\ {\text { the electron reaches coordinate } x=20 \mathrm{cm} ?}\end{array}$$