模型1:v0=0或v0与E平行的带电粒子,在恒定匀强电场中加(减)速直线运动;在交变匀强电场中,做周期性加(减)速直线运动. 例1 如图1所示,沿水平方向放置的平行金属板a和b,分别与电源的正、负极相连,a、b板的中央沿竖直方向各有一个小孔,带电的液滴从小孔的正上方的P点,由静止开始落下,先后穿出两个小孔后 Model 1: Charged particles with v0=0 or v0 parallel to E, plus (minus) linear motion in a constant homogenous electric field, and periodic (plus or minus) linear motion in an alternating uniform electric field. Example 1 As shown in Fig. 1, the parallel metal plates a and b placed in the horizontal direction are respectively connected to the positive and negative electrodes of the power source, and the centers of the a and b plates each have a small hole in the vertical direction. The charged droplets from the small holes P point directly above, falling from rest, passing through two small holes