论文部分内容阅读
根据杠杆的平衡条件F_1·l_1=F_2·l_2可知,当杠杆中的阻力、阻力臂一定时,要达到所用动力最小的目的,必须使动力臂最长.在通常情况下,连接杠杆中支点与动力作用点这两点所得到的线段是最长的.为此,要作出杠杆中的最小动力,应按照以下几个步骤进行:(1)找出杠杆的支点.找支点时,一要紧紧抓住支点的特征——杠杆绕着转动的固定点;二要平时注意观察物体究竟可以绕着哪一点转动;三要善于想象,把纸面上静止的杠杆在大脑想象中转起来,从而找出支点.(2)找最大力臂,确定动力的作用点:看支点到杠杆上的哪一点的距离最大,然后连接支点与这一点,得到最大的力臂,则该点就是最小动力
According to the balance condition of the lever F_1·l_1=F_2·l_2, when the resistance and the resistance arm in the lever are constant, the power arm must be longest to achieve the purpose of using the minimum power. In the normal case, the pivot point in the connection lever is The line segment obtained by these two points of power application is the longest. Therefore, to make the minimum power in the lever, follow the following steps: (1) Find the fulcrum of the lever. When the fulcrum is found, it must be tight. Grasp the characteristics of the fulcrum - the lever around the fixed point of rotation; Second, we must always pay attention to observe what the object can rotate around; Third, we must be imaginative, in the paper, the static lever on the paper in the brain imagination to find out Fulcrum. (2) Find the maximum strength and determine the point of power: see which point on the lever the greatest distance, then connect the fulcrum and this, get the maximum force arm, then this point is the minimum power