在教学《滑轮》时,学生实验结果存在严重分歧。A组:将一个滑轮固定在一定位置上,用线绳将两个钩码吊在定滑轮上,两个钩码不上也不下,说明定滑轮不省力也不费力,但改变了用力方向。B组:把50克的钩码套在定滑轮上,用测力计拉,只用了47克的力,说明定滑轮省力,而且改变用力方向。C组:他们说的不对,我们把50克的钩 When teaching “Pulley”, there are serious differences between students' experimental results. Group A: fixed a pulley in a certain position, the two hooks hanging with a rope in the fixed pulley, two hook code is not on nor under, indicating the fixed pulley is also less effort and effortless, but changed the direction of force. Group B: 50 grams of the hook code set in the fixed pulley, with a dynamometer pull, only 47 grams of force, fixed pulley effort, but also to change the direction of force. Group C: They said no, we put 50 grams of hooks