There are some differences. Quality refers to the quantity of a substance, which changes with the change of environment. For example, an object with a mass of 1KG is 1KG on the earth and 1KG on the moon, because the content has not changed! Weight is based on the value obtained by weighing, and it is measured on the earth with tools by using the gravity between the object and the earth. . . Conceptually, there are differences, but in mathematics, many people mix them together, because weight can represent the gravity of a certain mass object, so there is no need to ask for further research. Give it to me. I need to download the contents of the library urgently.