**Part A**

$\overline{){\mathbf{F}}{\mathbf{=}}{\mathbf{q}}{\mathbf{E}}}$

$\overline{){\mathbf{W}}{\mathbf{=}}{\mathbf{m}}{\mathbf{g}}}$

q = +1.6 × 10^{-19} C

m = 1.67 × 10^{-27} kg

g = 9.8 m/s^{2}

$\begin{array}{rcl}\mathbf{\Sigma}\mathbf{F}& \mathbf{=}& \mathbf{m}\mathbf{a}\\ \mathbf{qE}\mathbf{-}\mathbf{mg}& \mathbf{=}& \mathbf{0}\\ \mathbf{E}& \mathbf{=}& \frac{\mathbf{m}\mathbf{g}}{\mathbf{q}}\\ & \mathbf{=}& \frac{\mathbf{(}\mathbf{1}\mathbf{.}\mathbf{67}\mathbf{\times}{\mathbf{10}}^{\mathbf{-}\mathbf{27}}\mathbf{)}\mathbf{(}\mathbf{9}\mathbf{.}\mathbf{8}\mathbf{)}}{\mathbf{(}\mathbf{1}\mathbf{.}\mathbf{6}\mathbf{\times}{\mathbf{10}}^{\mathbf{-}\mathbf{19}}\mathbf{)}}\end{array}$

Part A

What is the strength of an electric field that will balance the weight of a proton?

Part B

What is the direction of an electric field that will balance the weight of a proton?

a) upward

b) downward

Part C

What is the strength of an electric field that will balance the weight of an electron?

Part D

What is the direction of an electric field that will balance the weight of an electron?

a) upward

b) downward