The first problem is that only the same charge can repel each other ... two particles with dots repel each other, so they must have the same charge (the same sign). What's the problem?

The second question ... SAT2 only requires that after mastering a certain speed (the speed of light must be a few tenths of a second ...), the object looks flat in the direction of motion ... and then this poor little stick figure who can't remember the body thickness will only be flat and short from ankle to toe.

As for why ... ask the physics master.