Select whether the physical reference can be selected by itself

Anytime, but not necessarily the most appropriate.

The selection of reference objects is often to facilitate the analysis of the problem and facilitate the solution of the problem, so whether the selected reference object is appropriate is related to whether the problem can be simplified. If the choice is not appropriate, it will only complicate the problem.

A general rule of thumb for choosing a reference: Whenever possible, choose something that is relatively stationary with most objects as a reference. This simplifies the problem by reducing the number of moving objects that need to be analyzed.

For example, on land, we choose the ground or an object that is stationary on the ground as a reference. Because most of the flowers, trees, houses, etc. on the ground are relatively still from the ground.

If we choose to drive the car, then many things on the ground have a relative motion relationship with the vehicle, which is very troublesome to analyze. If in the running compartment, we should take the carriage as a reference, so that many objects in the car are relatively static with the carriage, which is more convenient, if the ground outside the window is used as a reference object at this time, then everything in the car is relative to the outside world, and there are many objects to analyze, and it is very troublesome to involve the speed of the vehicle.

At any time, you can select different reference objects for different reference frames, and the corresponding objects have different motion states.

Yes. You like to be self-centered, don't you, that's kind of like me.

1. The "self" here refers to the "object" itself that you are studying;

2. Reference refers to the reference objects selected when studying the motion of objects or the system of things that do not move relative to each other;

3. According to whether Newton's laws of mechanics are true in the reference frame, the reference frame can be divided into two categories: inertial and non-inertial frames.

Who says you can't choose your own reference? References can be selected arbitrarily, but in the question, they must be selected according to the meaning of the question. For example, if you want to study the relative velocity of a car, you can't use the people in the car as a reference, but you can use the earth or an object at rest on the earth as a reference, and if you are relatively stationary, then you can use yourself as a reference to study the relative velocity of the car.

Anyway, relativity can be transferred, for example, it is known that the relative motion of A relative to B, and the relative motion of B relative to C, then it can be deduced, the relative motion of A relative to C. As for your misunderstanding, you don't understand the premise of choosing a reference, and you have to look at the research object and the motion relationship of the topic to determine the choice of reference--- which is the premise! In addition, to learn physics, we must learn and apply it flexibly, and of course, to do physics research, we must also cultivate rigorous thinking ability, but not more seriously!

1. The "self" here refers to the "object" (or particle) itself that you are studying.

For example, if you want to study the movement of a car, you can't use a car as a reference. If the object of study (oneself) is used as a reference, the "object" is always in a static state and loses its research significance.

2. If you sit in the car and do not move, when you take "you" as a reference, the car is stationary relative to you.

If you go from the front to the back of the car, the car will move forward relative to you.

The reference is arbitrary, dear! It is important to understand that movement is relative. For example, you see the car moving, but to the people in the car, the car and the driver are stationary. Generally the reference of the topic is the earth by default, if it is said.

The choice of reference is arbitrary, then I don't understand very well, I have to say the specific topic to give you the answer.

You can choose yourself, the reference is arbitrary, because matter is in motion, motion is unconditional, absolute and eternal, and rest is relative, conditional and temporary. So it is absolute motion and relative rest, and the reference at rest is arbitrary.

In the study of mechanical motion, the object that is pre-selected and assumed to be immovable as a reference is called a reference. (Generally not based on the research object).

Whether one is stationary or in motion depends on the object as the standard. The object that has been selected as the standard is called the reference.

For references, pay attention to the following two points:1Whether an object is in motion or at rest depends on which other object is used as the criterion.

This object that has been selected as a standard is the reference. 2.To determine whether an object is moving or stationary, it is determined whether there is a change in position between the object and the selected reference.

If there is a change in position, the object is in motion with respect to the reference object; If there is no change in position, the object is stationary with respect to the reference.

A reference system is a general term for a reference object and a coordinate system. Sometimes the reference object is simply called a frame of reference.

Note: 1) If the motion of an object is measured relative to a certain reference frame, when the object is not subjected to an external force or the combined external force is zero, it strictly remains stationary or moves in a uniform straight line, then this reference frame is called an inertial reference frame. That is to say, the frame of reference in which Newton's first law of motion is established is called an inertial frame of reference, referred to as an inertial frame; A frame of reference where Newton's first law does not hold is called a non-inertial frame of reference, or non-inertial frame for short.

A frame of reference that is stationary or moving at a uniform speed (straight line) with respect to an inertial frame of reference is also an inertial frame.

2) Experiments have proved that stars and solar systems (reference frames with the center of the star or the sun as the origin of coordinates and a straight line pointing to any star as the coordinate axis) are very accurate inertial frames. The Earth can be seen as an inertial frame with a fairly good approximation, so the Earth is usually chosen as the inertial frame of reference to study the motion of objects on the ground.

When dealing with kinematic problems, the choice of reference system is arbitrary, that is, it can be arbitrarily selected according to the convenience of solving the problem. Of course, relatively different frames of reference for the same object appear as different motions. However, when solving a dynamical problem, an inertial frame of reference must be chosen, otherwise Newton's laws of motion no longer hold.

3) The reference system used to be used as a reference system, and according to the "Physics Terminology (Basic Physics Part)" published by the National Natural Science Terminology Examination and Approval Committee in 1988, the reference system is not called the reference system.

The reference brother is used as a reference. Motion is absolute, and rest is relative. To describe a motion we need to first select an object as a reference, and once we have selected the object, then we need to assume that the object is immobile.

The reason why you can't understand it is because you are disturbed by the usual common sense, we usually say that the car is moving, the car is stopped, and there is also a reference, that is, the ground. In fact, when the car stops, you pass by, and you use yourself as a reference, the car is moving away from you.

Therefore, there is a conclusion: the reference object can be selected arbitrarily, and the same object may have different motion results if different reference objects are selected. We usually use the ground or an object that is not moving relative to the ground as a reference.

For the rest of the questions, you only need to compare the two objects given in the question. For example, in the car, we see the building moving backwards, and the search is that the building is compared with us, and we are talking about the situation of the building, so we (the people in the car) are the references. The clouds block the sun, the clouds move, and the sun is the reference.

The moon is blocked by clouds, the clouds are moving, and the moon leak is a reference.

Generally speaking, the ground is better.

The principle of arbitrariness: any object other than the object of study can be selected.

The principle of convenience: the reference object chosen should make our description of the object simpler and clearer. Unless otherwise specified, it is common to choose oneself or an object fixed on the ground as a reference.

Become the 8th fan.

The selection of references in physics should be followed:

1. The principle of "generality".

The so-called "general" principle means that when describing the motion of objects on and near the ground, the ground is generally selected as the reference, or the ground is defaulted as the reference.

2. The principle of "demand".

Although the choice of reference objects is arbitrary, it cannot be arbitrary, and sometimes we have to choose the appropriate object as a reference object according to the actual situation and needs.

3. The principle of "convenience".

The principle of "convenience" refers to the study of the selection of reference objects from convenience to simplify the motion of objects. If the reference is not selected properly, it can sometimes complicate the problem.

4. The principle of "identity".

When studying the relative motion of multiple objects, the same object is often selected as a reference object to analyze the motion process of the research object, which is the principle of "identity".

You can choose clouds, street lamps, and all objects that move relative to the moon.

The reference object is generally chosen what you feel is not moving.

You sit in the car and watch the trees on the side of the road go back.

Illuminating things is relative to yourself and not understanding, comparing.

Such as yourself, the person next to you, the car, etc.

You're sitting on a train, and sometimes it's hard to tell if it's you.

The train is moving, or the train next to it is moving, because.

The only thing you can see for you is the train you are sitting on and next to it.

If you don't feel like you're moving, you'll feel it.

The train next to it is moving.

If you don't understand the train next to you, you feel self.

I'm moving! It's actually very simple to get used to it for a while!

There are two wrong questions on the last one.

The second option is C 4A

Motion or stillness as opposed to the eye.

1. There is nothing on the skin of the world's nuclear friends that is static, the reference object is relative, and when observing the object, I do not have the action of looking for the reference object, but only a feeling;

2. As long as you feel that an object is moving, then other objects near it that we think are not moving, can be said to be a reference, and it depends on the question and options of the question;

3. The reference object can be any thing on the earth, and what it plays is to change the bad light, the role of reference, and the general selection of the reference object is to give the best interpretation of the problem you want, so that the problem is more simplified.