根据支点相对于动力与阻力作用点的位置关系,杠杆可以分为三类。请注意下列每个例子中支点的位置。第一类支点在动力与阻力作用点之间,支点与动力作用线之间的距离(动力臂)大于支点与阻力作用线之闻的距离(阻力臂),这类杠杆是省力杠杆。反之,则是费力杠杆,能增加阻力的作用距离 According to the position of the fulcrum relative to the point of action of the force and resistance, the levers can be divided into three categories. Please note the location of the fulcrum in each of the following examples. The first type of fulcrum between the point of power and resistance, the distance between the fulcrum and the line of action (power arm) is greater than the distance between the fulcrum and the line of resistance (resistance arm). Such levers are labor-saving lever. On the contrary, it is laborious lever, can increase the resistance of the role of distance