Electric Field Rod

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$_3$

The rod below is 1.4 m long and carries a charge of -8 x 10$^{-8}$. Point A is 0.7 m from the center of the rod. Find the electric field at point A due to the bottom 1/8th of the rod, colored blue below.

Two concentric loops are shown below, with a distance between them Y = 0.4 m, a radius Z = 0.1 m. The loop on the left has a charge of +9 nC and the loop on the right has a charge of -9 nC. Find the electric field at point X, which is directly in the middle of the loops.