How to find the right reference? How to determine the reference

Frame of referenceThe choice is arbitrary, but it should be based on the principle of ease of observation and the simplicity of the description of the motion, and the ground is often chosen as the reference frame for the study of the motion of objects on the ground.

The general title is not indicated, and the reference system is indicated.

It's the ground. 1 It is assumed in advance that the frame of reference will not move.

2 Choose a different frame of reference and the results will vary.

3 The selection of a frame of reference can be arbitrary.

4 in the same frame of reference.

its nature. Arbitrary: The selection of the frame of reference is arbitrary, but should be based on the principle of ease of observation and as simple as possible in the description of the motion.

Variability: Different frames of reference are selected for the same movement, and the observations are generally different. For example, a passenger sitting in a moving car, with the ground as the frame of reference, the passenger is in motion, but if the car is used as the frame of reference, the passenger is stationary.

It is important to note that when studying the motion of an entity, the lower the objective rate of motion of the selected reference object (relative to the rate of motion of the celestial center), the more objective the motion of the entity is.

The spatial position of the center of the universe does not change with the evolution of the universe. That is, the heart of Zeus is always absolutely still.

There is no doubt that in the case of subjective motion (the motion of the non-celestial mind of the reference), the smaller the objective rate of motion of the chosen reference, the closer the motion of a particular entity is to the objective motion; Conversely, the greater the objective velocity of the reference object, the more the motion of a particular entity deviates from the objective motion.

Thus, in the visible universe: the closer to absolute rest is taken as a reference, the more objective the motion of a particular entity is; Conversely, if the object is subject to a higher rate of objective motion, the less objective the motion of a particular entity is.

Therefore, for human beings, the subjective motion of a specific entity observed with the following things as a reference is closer to the objective motion in turn: the earth energy center (i.e., the earth center), the solar system energy center, the galaxy energy center, the local galaxy group energy center, and the visible universe energy center.

The reference object is not accurate and inaccurate.

Only the coincidence of finding.

Like what. The ship's stuff fell into the water.

Things drift down the river.

The boat then turns around and chases something.

At this time, the water level reference is the best, too.

Because things don't move relative to water.

Calculate the relative velocity of the boat and the water.

It's easy. General, for example, people running, using the ground or scenery as a reference, the general situation, and another example, seeing a certain flying object on an airplane, stationary, is to use the airplane as a reference, otherwise it is necessary to analyze the specific topic, it is very important to find the right reference, otherwise the movement and stationary hanging

How to choose the reference object, and how to judge the motion of the object after selection?

Refer to the mantra of the envy of the goods.

1. The sun rises from the east: the sun is moving, and what moves is not the reference, so the ground is the reference.

2. The moon hides in the clouds: the moon is moving, the moon is not a reference, the clouds are a reference.

3. Small bamboo row in the middle reaches of the river: the bamboo row is moving, the bamboo row is not a reference, and the ground is a reference.

4. Walking on both sides of the towering green mountains: the green mountains are walking, the green mountains are not a reference, the river or bamboo row is a reference.

How to judge the reference:

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) under normal circumstances, the ground orange crack surface is mostly used as the reference.

The reference object can be arbitrarily selected, and different reference objects can be selected to describe the motion state of the same object, and different conclusions may be drawn, so motion and rest are relative. When studying the mechanical motion of an object on the ground, an object that remains relatively stationary from the ground is usually used as a reference.

The role of the reference

A reference body can be taken aside to determine the position of an object and to describe its mechanical motion as a standard object. In order to numerically represent the position of an object, a coordinate system can be set on the reference body, and both the reference system and the reference coordinate system can be arbitrarily selected, but the same motion is represented differently in different reference frames.

The appropriate reference body is usually selected according to the actual situation of the problem. For example, when a rocket takes off from the earth's surface, it is advisable to use the earth as a reference body; When a spacecraft becomes an artificial planet orbiting the Sun, it is advisable to use the Sun as a reference body. It follows that all mechanical phenomena can only be observed, described, and studied in relation to the selected frame of reference.

There can be different reference coordinate systems on the same reference system, and although their values for the position coordinates of the same object are different, they are related by definite geometric relations. In order to quantitatively describe the motion of an object, a reference coordinate system is often used directly.

For example, if you want to measure how fast a car is, you can choose a tree or stone on the side of the road as a reference, and if you choose a moving object, such as a moving bicycle, then.

What you measure is the relative velocity of the car relative to the bike.

At this time, you can understand that the bicycle does not move, and the speed of the vehicle plus the speed of the bicycle is the speed of the car. (When the direction is the same, the speed of the bicycle is reduced, and vice versa).

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.