进入高中任教以来,听了很多教师的课,从中学习了不少可用的东西,受益匪浅.最近听到有些教师讲到曲线运动这一章时,涉及到曲线运动的特点有几句话,我认为值得商榷,比如:曲线运动的速度时刻不为零,曲线运动的加速度时刻不为零,合外力方向与速度方向时刻不共线.特别在遇到下面几个题目时,我产生了些许疑问. Since I entered high school as a teacher, I have listened to a lot of teachers’ lessons and learned a lot of useful things from it. I have benefited a lot from it. Recently, when I heard some teachers talk about the curvilinear movement, there are a few words about the characteristics of the curve movement. I think it is worth discussing, for example, the velocity of the curve motion is not zero at all, the acceleration moment of the curve motion is not zero, and the external force direction is not in line with the speed direction. Especially when I encounter the following problems, I have produced a little doubt.