不考虑摩擦,将条件理想化是物理学中处理问题常用的方法,学生往往提出考虑摩擦怎么办的实际问题。如果只以知识有限为理由搪塞一下的话,不仅不能打消学生头脑中的疑问,还会抑制学生认真探索的精神。所以,我们在物理复习课中,曾尝试引导学生,将举重螺旋简化,应用力的正交分解法、功的原理,求解了一个考虑摩擦的举重螺旋问题,现介绍如下: 如图1所示方牙举重螺旋,手柄旋转一周,托盘上的重物随同螺母上升一个螺距t。若已知手柄端到螺旋轴线的距离L,螺旋平均直径d,螺旋升角λ、螺旋面摩擦系数f,托盘上的 Irrespective of friction, idealizing conditions is a common method of dealing with problems in physics, and students often come up with practical questions about how to deal with friction. If we only condemn it on the basis of limited knowledge, we must not only dispel doubts in students’ minds, but also inhibit the spirit of serious exploration by students. Therefore, in the physics review class, we tried to guide students, simplified the weight spiral, applied the force orthogonal decomposition method and the principle of work, and solved a friction lifting weight spiral problem. Now it is introduced as follows: The square tooth lifts the helix, the handle rotates one turn, and the weight on the tray rises with the nut by a pitch t. If the distance L from the handle end to the axis of the screw is known, the mean diameter d of the spiral, the angle of helix λ, the coefficient of friction of the spiral surface f, on the pallet