【中文版】

杠秤是一种称重工具，通常用于测量物体的重量。它是由一个带有刻度的杠杆和一个秤盘组成的。在使用杠秤时，将待测物体放在秤盘上，通过移动杠杆来平衡物体的重量，从而读出物体的重量。

杠秤可以被视为一种等臂杠杆，因为它的两臂长度相等。当物体放在秤盘上时，杠杆的一端向下倾斜，另一端向上倾斜。为了平衡物体的重量，需要将杠杆向上倾斜的一端向下压，直到两端的力矩相等。此时，杠杆处于平衡状态，可以读出物体的重量。

杠秤的优点在于它可以直接测量物体的重量，而不需要考虑物体的形状和大小。此外，杠秤的刻度通常是均匀的，因此可以准确地读出物体的重量。

总的来说，杠秤是一种简单而实用的称重工具，广泛用于日常生活和工业领域中。它利用了等臂杠杆的原理，通过平衡物体的重量来测量其重量。

【英文版】

The lever scale is a weighing tool commonly used to measure the weight of objects. It consists of a calibrated lever and a weighing pan. When using the lever scale, the object to be measured is placed on the weighing pan and the lever is moved to balance the weight of the object, thus reading the weight of the object.

The lever scale can be regarded as an equal-arm lever, because its two arms have equal lengths. When the object is placed on the weighing pan, one end of the lever tilts downward and the other end tilts upward. To balance the weight of the object, the end of the lever that tilts upward needs to be pressed down until the moments on both ends are equal. At this point, the lever is in balance and the weight of the object can be read.

The advantage of the lever scale is that it can directly measure the weight of objects without considering their shapes and sizes. In addition, the calibrations on the lever scale are usually uniform, so accurate readings of the object's weight can be obtained.

Overall, the lever scale is a simple and practical weighing tool widely used in daily life and industrial fields. It utilizes the principle of equal-arm levers to measure an object's weight by balancing it.