一、题设条件的可能性形成的多解例1 质量为m, 带电量为+q的滑环套在水平固定且足够长的绝缘细杆上,如图 1所示,整个装置处于方向垂直纸面向里,磁感应强度为B的匀强磁场中,现给滑环一个水平向右的瞬时冲量I,使其开始运动,求滑环运动后的整个过程克服摩擦力所做的功．(不计空气组力) First, the possibility of the formation of multiple solutions to the conditions of the formation of a solution 1 mass m, the charge of +q slip ring sets in the horizontal fixed and long enough insulating rod, as shown in Figure 1, the entire device is in the vertical direction With the paper facing inwards and the magnetic field with a magnetic induction intensity of B, the momentary impulse I of the slip ring is presented to the right of the slide ring to make it move, and the entire process after the slip ring motion is overcome to overcome the work done by the friction force. (Excluding air force)