Решение задачи по физике раздел 74 пункт 6 электро

6. A ball weighing 90 mg is suspended on a non-conductive thread and has a charge of 10 nC. After a point charge of a different sign was placed under the ball at a distance of 10 cm from it, the thread tension doubled. Find the magnitude of this charge.

Detailed solution. Decorated in Microsoft Word 2003. (Target decided to use formula editor)