When you travel on roads like the M1 you see pylons with cables that have colored spheres. Seeing that between two towers the cable is perfectly horizontal and there are only 4 of these spheres, which have a constant charge Q.

1. What would the system of equations that describes this look like if the spheres are at a distance L, such that you must consider the electric force exerted only by nearby charges.

2. The tension in the cable between the tower and the first sphere is T, which is the same between the last sphere and the tower. Find the values of the tensions in the string.