Warning: fopen(/var/www/storage/cache/cache.catalog.language.1767115981): failed to open stream: No space left on device in /var/www/opencart/system/library/cache/file.php on line 49Warning: flock() expects parameter 1 to be resource, bool given in /var/www/opencart/system/library/cache/file.php on line 51Warning: fwrite() expects parameter 1 to be resource, bool given in /var/www/opencart/system/library/cache/file.php on line 53Warning: fflush() expects parameter 1 to be resource, bool given in /var/www/opencart/system/library/cache/file.php on line 55Warning: flock() expects parameter 1 to be resource, bool given in /var/www/opencart/system/library/cache/file.php on line 57Warning: fclose() expects parameter 1 to be resource, bool given in /var/www/opencart/system/library/cache/file.php on line 59Warning: fopen(/var/www/storage/cache/cache.catalog.language.1767115981): failed to open stream: No space left on device in /var/www/opencart/system/library/cache/file.php on line 49Warning: flock() expects parameter 1 to be resource, bool given in /var/www/opencart/system/library/cache/file.php on line 51Warning: fwrite() expects parameter 1 to be resource, bool given in /var/www/opencart/system/library/cache/file.php on line 53Warning: fflush() expects parameter 1 to be resource, bool given in /var/www/opencart/system/library/cache/file.php on line 55Warning: flock() expects parameter 1 to be resource, bool given in /var/www/opencart/system/library/cache/file.php on line 57Warning: fclose() expects parameter 1 to be resource, bool given in /var/www/opencart/system/library/cache/file.php on line 59Задача 31392.
Четыре положительных заряда по 10 Кл каждый помещены в вершинах квадрата. Какой отрицательный заряд надо помесить в центре квадрата, чтобы вся система находилась в равновесии?
