AP Physics C Electricity

Two objects, whose charges are +3 nC and -2 nC, are separated by 1.0 mm. Find the magnitude of the attractive force that either charge exerts on the other.

In the figure below, L = 1.0 mm, q$_1$ = +3 nC, q$_2$ = -2 nC, and q$_3$ is +4 nC. Find the magnitude and direction of the net electrostatic force on q$_3$

Two parallel charged plates, one with a surface charge density of $\eta_1$ = 40 $\frac{nC}{m^2}$ and another, $\eta_2$ = -60 $\frac{nC}{m^2}$. Find the total electric field between the plates. (note this is not a capacitor)

An electron is released from rest at the surface of a very large plate of charge density -50 $\frac{nC}{m^2}$ . How long will it take for the charge to move 10 cm?