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1明确W=FS中F与S的含义及关系做功的两个必要因素:①作用在物体上的力;②该物体在这个力的方向上通过的距离。看似简单的两句话,却给解题带来了许多麻烦。例如用40牛顿的力把一个5牛顿的足球踢飞,足球在空中飞行了15米后落地,又向前滚动了10米后停止,则脚对足球做的功为()A.100
1 Defining the meaning and relationship of F and S in W=FS Two necessary factors for doing work: 1 The force acting on the object; 2 The distance the object passes in the direction of this force. The seemingly simple two sentences have brought a lot of trouble to solving problems. For example, with a force of 40 Newton kicking a 5 Newton soccer ball, the football flies in the air for 15 meters and then lands. After rolling forward for another 10 meters, it stops and the foot’s contribution to the football is A.100