一、微量杆秤的设计思想杠杆平衡条件是初中物理的一项重要的教学内容。通常我们将杠杆根据动力臂和阻力臂的大小,分为三类,分别是省力杠杆、等臂杠杆、费力杠杆;应用有剪铁皮的剪刀、天平、理发用的剪刀等。常见的杆秤,如果将秤砣施加的力看作是动力,那么就属于省力杠杆,如图1所示。这种杆秤,动力臂大于阻力臂,属于省力杠杆。所称物体的质量远远大于秤砣的质量。而微量杆秤,所称量的物体的质量都比较小(例如直接称量一枚大头针的质量),设计的思想是将常见杆秤的秤砣与被称量的物体调换一下,如,常见杆秤的秤砣,在微量 First, the design of micro rod scale lever balance conditions is an important junior high school physics teaching content. Usually we will lever according to the size of the power arm and resistance arm, divided into three categories, namely, saving lever, arm lever, laborious lever; the application of scissors with scissors, scales, scissors and other haircut. Common rod scale, if the force applied by the scale 砣 as a power, then it is labor-saving lever, as shown in Figure 1. This rod scale, power arm is greater than the resistance arm, which is labor-saving lever. The quality of the object is much larger than the quality of the scale. The micro rod scale, the quality of the objects weighed are relatively small (for example, directly weighing the quality of a pin), the design idea is to replace the common weighing scale scales 被 and weighed objects, such as the common scales scale 砣 杆, In trace