2004年高考理科综合第21题是带电摆在重力和电场力的作用下,先做匀加速直线运动,然后做圆周运动的综合性选择题.此题运用了动能定理、矢量的合成与分解、能量守恒、圆周运动等重要知识内容,而且还具有题型基础好、变展合理性强等特点,所以,只要在原有基础上稍加扩充和变化,就可 The twenty-first issue of the 2004 college entrance examination science synthesis is the electrified pendulum under the action of gravity and electric field force, first to do uniform acceleration linear motion, and then to do a comprehensive multiple choice question of circular motion. This question uses the kinetic energy theorem, vector synthesis and decomposition, Energy conservation, circular motion and other important knowledge content, but also has a good basis for the type of questions, the characteristics of strong rationality and so on, so, as long as the original basis of a slight expansion and changes can be