Задача 30229.

The surface charge density of an infinitely extended the vertical plane equal to 400 SCLC / m ^ 2. By plane thread suspended charged ball of mass m = 10 has defined charge Q of the ball, if the thread forms an angle of 30 degrees.

Detailed solution with a short recording conditions, laws and formulas used in the decision, the withdrawal of the calculation formula and the answer.
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