主要区别-质量与重量

在日常使用中，我们可以互换使用质量和重量这两个术语。不过，两者在技术上有区别。质量和重量的主要区别在于，质量是对物体中物质数量的测量，而重量是对物体在引力场中所感受到的力的测量。

什么是群众(mass)？

Mass is a measurement of the amount of matter in a body. There are two separate contexts in which mass becomes important. Firstly, the mass of a body attempts to resist acceleration whenever a force is applied on a body. This reluctance by an object to resist acceleration is called inertia and so in this context, the mass is referred to as inertial mass (). If a resultant force  acts on the body, the acceleration that can be produced is inversely proportional to the object’s mass, such that:

Secondly, mass is also the property that determines the gravitational force between two objects. In this context, mass is referred to as gravitational mass (). The gravitational force of attraction between two objects with masses  and  , separated by a distance  can be given by,

where  is called the universal gravitational c***tant, with  6.67×10-11 m3 kg-1 s-2. (Note: gravitational mass can be further subdivided into active gravitational mass and passive gravitational mass, but that is a distinction we will not go into).

惯性和引力是两个独立的东西，物体的惯性质量没有理由等于引力质量。然而，没有实验证明两者是不相等的。质量是基本物理量之一，在国际单位制中，质量以千克表示。一套传统的天平测量质量。由于物体被添加到天平的两侧，重力被“抵消”，你所做的测量最终变成了质量的比较。

什么是重量(weight)？

Weight is the gravitational force experienced by a body in a gravitational field. If the weight of the body is given by  , then it is given by

where  is the gravitational field strength. Comparing with the equation we had for gravitational mass, we then have where  is the gravitational mass of the body that forms the gravitational field that the mass  is in.

重量是一种力，以牛顿（N）为单位。由于重量不仅取决于物体本身的质量，而且还取决于物体周围物体的质量以及与其他物体的距离，因此重量可以在不同的地方变化。例如，月球表面的引力场强度大约是地球表面引力场强度的六分之一。因此，如果两个质量相同的物体中的一个在地球上，另一个在月球上，它们仍将承受不同的重量。月球上的物体“重量”将减少六倍！浴室磅秤测量你的体重，因为它记录了你被拉下来的力量。

A set of bathroom scales measures weight. You’d notice a 16% “weight loss” if you were to take these scales to the Moon and weigh yourself there (however, your mass would still be the same)!

群众(mass)和重量(weight)的区别

它测量什么

质量是对物体中物质数量的测量。质量抵抗加速度，质量也产生引力。

重量是物体由于重力而受到的力。

易变性

物体的质量不变，这取决于它的位置。

物体的重量取决于周围物体的质量和它们之间的距离。

数量的性质

质量是一个标量。

权重是一个向量。

单位

质量以千克为单位。

重量以牛顿为单位。

Image Courtesy

“How to Weigh a Dog: part 1” by Stephanie Sicore (Own work) [CC BY-SA 2.0], via flickr