The coordinates of the center of mass are equal to the weighted average of all points relative to each coordinate. The center of mass, referred to as the center of mass for short, refers to an imaginary point on the material system where mass is concentrated. Unlike the center of gravity, the center of mass does not have to be in a system with a gravitational field. It is worth noting that unless the gravity field is uniform, the center of mass and the center of gravity of the same material system are usually not on the same imaginary point.
If different coordinate systems are selected, the specific values of the centroid coordinates will be different, but the relative position of the centroid relative to each particle in the particle system has nothing to do with the selection of coordinate systems. The center of mass of a particle system is only related to the relative position of the mass and distribution of each particle.
How to learn math well
Review, summarize and improve. It is very necessary to make a chapter summary. In junior high school, it is the teacher who gives the students a summary, which is meticulous, profound and complete. In the third year of senior high school, I made my own summary, but the teacher not only refused to do it, but also said where to take the exam, where to take the exam, leaving no review time, and did not clearly point out the time to make the summary.
Accumulate information and arrange it at any time. Pay attention to accumulating review materials. Organize class notes, exercises, unit tests and various papers in chronological order. Every time you read it, mark the key content of the next reading on it. This way, the review materials can be more refined and clear at a glance.
Carefully choose extracurricular reading materials. Generally speaking, it won't matter if junior high school students don't pay attention to extracurricular reading. High school is different. Senior high school mathematics tests students' ability to solve new problems. As a high school student, if you just focus on your own teacher, then no matter how high the teacher's level is, it will inevitably have great limitations.
Therefore, if you want to learn math well, you must open a door and look at the outside world. Of course, don't start your own business, start a new stove. Once divorced from school teaching and the teaching system of your own teacher, you will get twice the result with half the effort.