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2012年北京高考理综物理试题的压轴题(第24题),可谓是一道考察物理思想方法的好题。[原题]匀强电场的方向沿x轴正向,电场强度E大小随x的分布如图所示。图中E_0和d均为已知量。将带正电的质点A在O点由静止释放,A离开电场足够远后,再将另一带正电的质点B放在O点也由静止释放,当B在电场中运动时,A、B间的相互作用力及相互作用能均为零;B离开电场后,A、B间的相互作用视为静电力作用。已知A的电荷量为Q,A和B的质量分别为m和m/4,不计重力。
2012 Beijing college entrance exam physics test questions (27 questions), can be described as a good way to examine the physical thinking method. [Original] Even the direction of the strong electric field along the positive x-axis, the size of the electric field strength E distribution with x as shown. The figure E_0 and d are known quantities. The positively charged particle A is released by the static at point O, A is far enough away from the electric field, and then another positive particle B is released by the static at point O. When B moves in the electric field, A and B The interaction force and the interaction between them can all be zero; B After leaving the electric field, the interaction between A and B is regarded as the electrostatic force. It is known that the charge of A is Q, the masses of A and B are m and m / 4, respectively, regardless of gravity.