The Slug as a Mass Unit

What is a Slug?

Slug 是什么？

The slug is the unit of mass in the US common system of units, where the pound is the unit of force. The pound is therefore the unit of weight since weight is defined as the force of gravity on an object. While the pound force and pound weight are the widely used units for commerce in the United States, their use is strongly discouraged in scientific work. The standard units for most of scientific work are the SI units.

slug 是美国常用单位制中质量的单位，其中磅是力的单位。因此，磅也是重量的单位，因为重量被定义为作用在物体上的重力。虽然磅力和磅重量是美国商业中广泛使用的单位，但在科学工作中强烈不建议使用。科学工作中的标准单位主要是SI单位。

A newton can be seen to be the force required to accelerate 1 kg of mass at 1 m/s². To accelerate a 1 kg mass at 9.8 m/s² would require 9.8 newtons, so on Earth the weight of 1 kg is 9.8 newtons. Similarly, a pound can be seen to be the force required to accelerate 1 slug of mass at 1 ft/s². Since the acceleration of gravity in US common units is 32.2 ft/s², it follows that the weight of one slug is 32.2 pounds.

牛顿是使1千克质量以1米每二次方秒加速所需的力。要使1千克质量以9.8米每二次方秒加速，需要9.8牛顿，因此在地球上1千克质量的重量是9.8牛顿。同样，磅是使1slug质量以1英尺每二次方秒加速所需的力。由于在美国常用单位中重力加速度是32.2英尺每二次方秒，因此1slug的重量是32.2磅。

The comparison of the slug and the pound makes it clear why the size of the pound is more practical for commerce. But at the precision obtainable in current scientific work, it is undesirable to have the weight of an object as a standard because the value of g does change measurably at different points on the Earth. It is much better to have a standard in terms of mass. The standard kilogram is the mass reference for scientific work.

slug 和 pound 的比较清楚地说明了为什么磅更适用于商业。但就当前科学工作中可达到的精度而言，将物体的重量作为标准是不合适的，因为重力加速度g在地球的不同地点会明显变化。用质量作为标准要更好些。标准千克质量是科学工作中质量的参考标准。

These demonstration objects were photographed in Zig Peacock's excellent demonstration laboratory at the University of Utah in Salt Lake City.

这些演示物体是在犹他大学盐湖城分校的Zig Peacock出色的演示实验室中拍摄的。