题目

In this age of Internet chat, video games and reality television, there is no shortage of mindless activities to keep a child occupied. Yet, despite the competition, my 8-year-old daughter Rebecca wants to spend her leisure time writing short stories. She wants to enter one of her stories into a writing contest，a competition she won last year.As a writer I know about winning contests, and about losing them. I know what it is like to work hard on a story only to receive a rejection slip from the publisher. I also know the pressures of trying to live up to a reputation created by previous vict如图所示，一带正电的物体位于M处，用绝缘丝线系上带正电的小球，分别挂在P1、P2、P3的位置，可观察到小球在不同位置时丝线偏离竖直方向的角度不同．关于此实验得出的结论，下列说法中正确的是(　　)A. 电荷之间作用力的大小与两电荷的带电性质有关B. 电荷之间作用力的大小与两电荷间的距离有关C. 电荷之间作用力的大小与两电荷所带的电量无关D. 电荷之间作用力的大小与丝线的长度有关