群眾(mass)和重量(weight)的區別

在日常使用中，我們可以互換使用質量和重量這兩個術語。不過，兩者在技術上有區別。質量和重量的主要區別在於，質量是對物體中物質數量的測量，而重量是對物體在引力場中所感受到的力的測量。...

主要區別-質量與重量

在日常使用中，我們可以互換使用質量和重量這兩個術語。不過，兩者在技術上有區別。質量和重量的主要區別在於，質量是對物體中物質數量的測量，而重量是對物體在引力場中所感受到的力的測量。

什麼是群眾(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).

慣性和引力是兩個獨立的東西，物體的慣性質量沒有理由等於引力質量。然而，沒有實驗證明兩者是不相等的。質量是基本物理量之一，在國際單位制中，質量以千克表示。一套傳統的天平測量質量。由於物體被新增到天平的兩側，重力被“抵消”，你所做的測量最終變成了質量的比較。

什麼是重量(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.

重量是一種力，以牛頓（N）為單位。由於重量不僅取決於物體本身的質量，而且還取決於物體周圍物體的質量以及與其他物體的距離，因此重量可以在不同的地方變化。例如，月球錶面的引力場強度大約是地球錶面引力場強度的六分之一。因此，如果兩個質量相同的物體中的一個在地球上，另一個在月球上，它們仍將承受不同的重量。月球上的物體“重量”將減少六倍！浴室磅秤測量你的體重，因為它記錄了你被拉下來的力量。

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)!