Holistic method, please consult the physics master! Ask the experts in theoretical physics!

Hello landlord: First of all, we must know what is the holistic method.

The following is from the encyclopedia: The holistic method refers to the method of analyzing and studying the entire system or the entire process in a physical problem. In mechanics, several objects are regarded as a whole as the object of study, and when the force is analyzed, only the force of the object outside the whole object on the whole (external force) is analyzed, and the interaction force between the whole (internal force) is not considered.

1.Characteristics of the thinking of the holistic approach:

The holistic approach is the thinking process from the local to the global, and it is the application of the holistic principle in systems theory to physics.

2.Advantages of the holistic approach:

By analyzing the physical problems through the holistic method, we can find out the overall force of the system and the force of the whole process, and reveal the essence and variation law of things as a whole, so as to avoid the cumbersome calculation of intermediate links and solve the problem flexibly. The holistic approach is usually used when analyzing the action of external forces on a system.

3.Holistic method solution steps:

Define the whole process of the system or movement under study. Draw a force diagram of the system and a schematic diagram of the whole process of movement. Find the relationship between unknown quantities and known quantities, and select the appropriate physical law column equation to solve.

The overall method of this paragraph applies to the question type.

The question of the connecting body, the stacking of Arhat wooden blocks asks. Question: The holistic method requires that all parts of the object have the same state of motion, and that a is the same (acceleration).

If you put two objects as a system, and the acceleration direction of the two objects is different (e.g., a fixed pulley connects two objects), you still need to use the isolation method. If the acceleration is the same, you can take the method of isolating first and then integrating! It depends on the question, you can put the question up, let's see.

If you still have questions, you can m me, the lord of the watchtower!

With the holistic approach, you first need to identify the object of study, and then distinguish the relationship between the objects. The holistic method is to treat several objects as a system as the object of study, and when analyzing the force, only the force exerted by the object outside the whole object on the whole (external force) is analyzed, and the interaction force between the whole (internal force) is not considered.

What you said about fixed pulley, acceleration and so on depends on the situation. In fact, the holistic approach only makes it easier for you to describe when you solve the problem.

What method is just 1 scale, don't drill the tip of the horns.

After analyzing the problem clearly, you will naturally know how to solve it, and as for the solution, you can call it how you want.

Where there is an idea, there is a method.

I'll answer your first question based on what I've learned in my previous electives, but I honestly don't know, and I won't be able to meet your requirements. However, if you really want to know what string theory says, you must at least learn general relativity and quantum field theory.

String theory was developed to solve the problem of gravitational sonization, or to unify general relativity and quantum mechanics, and the mathematically self-consistent string theory would give a limit to the space-time dimension.

The term string theory has two meanings, one is a general term for all such theories, and the other specifically refers to the Bose string theory that preceded the creation of superstring theory. This theory requires a space-time dimension of 26 dimensions, which is much higher than the 4-dimensional space-time of general relativity. Later, it was discovered that when supersymmetry was introduced, the self-consistent dimension of the theory was 10 dimensions.

Supersymmetry refers to the existence of a supersymmetrical partner in all particles, many of which we have not discovered. It is not enough to directly verify the predictions of string theory, but it is still possible to find supersymmetric particles (it seems that they have not been found yet?). ）。

String theory is to find a mathematical theory that can unify general relativity and quantum mechanics, and the first criterion to look for is self-consistency (this is actually very bad, because at least until a few years ago, when I studied string theory, it could only qualitatively give general relativity and quantum mechanics, but quantitatively did not match), as a result, people found that there are five self-consistent string theories, which are the specific five I have not figured out, and these five string theories can be seen as an 11-dimensional thing called m-theory at different limits. (Just like when focusing on the earth's surface, we can use 2D spherical geometry, but we can also look at the universe and thus describe it in 3D Euclidean space).

There is no experimental basis for high-dimensional space-time or something, and it is purely a last resort for the sake of self-consistency of theory. In my mind, supergravity should not belong to the category of string theory, but is different from string theory in another attempt to unify general relativity and quantum mechanics.

The maximum static friction between the two wooden blocks on the right side is mg, and under the action of this static friction force, a wooden block on the upper right side and two wooden blocks on the left side move together according to the acceleration a, a = mg (m + m + 2m) = g 4

The tension of the string on the two wooden blocks on the left:

2m+m)a=3m* g 4=3 mg 4 The static friction between the two wooden blocks on the left: 2ma=2 mg 4< mg, which meets the requirements, so the tensile force of the string on the left two wooden blocks 3 mg 4 meets the requirements of common acceleration motion.

So b is correct.

Resources.

Let the maximum tensile force of the rope be f1, and let the friction between objects be f

Analyze the two objects on the right f-f1=3ma f1-f=ma analyze the force on the large object on the left f=2ma, then f1=3ma, when the static friction force is the largest, the tensile force is the largest, and analyze the force on the small object on the right mg-f1=ma=f1 3

then mg=4f1 3

F1=3 mg4 so choose B

Two objects are regarded as a whole, and the internal forces cannot be considered, that is, the internal forces of the two are not considered.

But you need to choose a frame of reference for the two of them, it must be an inertial frame of reference, generally choose the earth...

But it doesn't necessarily mean that the overall acceleration is the same as the acceleration of these two objects.

The premise must be that the two objects are relatively stationary. Otherwise, it can't be the same.

For example, the masses of these two objects are m1 and m2. The resultant external force on this whole is set to f.

If they are relatively stationary: f = (m1+m2) *a, if they are not relatively stationary: f = m1*a1 + m2*a2.

If they don't want to be at rest, then it doesn't make sense for you to use the holistic method. It must be looked at in isolation, and then all use the earth as a frame of reference. Because the earth is a barely inertial frame of reference. Do both Niu 1 and Niu 2 have to satisfy the inertial frame of reference.

Right, because they can be seen as a, let's say, you can think of yourself as a lot of small molecules made up and then they accelerate the same right, right.

The integral method is generally used in a system composed of multiple objects, and the integral method and the isolation method are applied at the same time, the integral method is generally used to find the acceleration of the system when the system has the same motion state or to find the external force of the system, and the isolation method is generally used to find the internal force of the interaction within the system. Do you have a title, put it up and make one.

Generally, when two or more are in contact with each other and there is an interaction force, the integral method and the isolation method are usually used together, so that the integral method is a formula, and the isolation method is a formula, and it is easy to answer the answer.

In the case of force analysis, if the force inside the object has no effect on the analysis results, the object can be analyzed as a system as a whole.

For example, two objects A are stacked on a rough desktop on top of B and below, and A is pulled at a constant speed with a force of 2N, and AB does not slide relative to each other, so that B is subjected to the friction of the table.

In this case, it is clear that the friction between AB has no effect on the analysis results due to the balance of forces between the two ABs. If you can treat AB as a whole, and analyze it as a whole, it is easy to see that the friction force of B on the table is 2N.

Choosing B, first of all, because A and C are connected by a light rope, they have the same speed at all times. And B is subject to the frictional forces of A and B respectively, and since the friction that C can provide is greater than the friction that A can provide, the object B must move with C. From this, we find that B and C are relatively stationary, which can be regarded as an object, the overall cavity of BC is pulled to the left, the tension of the rope to the right and A is given to the friction force, and the balance of the force is F = F (A to BC) F (ground to BC) T (rope tension) = 1n 6n 1n = 8n Therefore, it should be noted that the friction between B and C is less than the maximum static friction, and the friction between B and C is 3N (the maximum friction, or sliding friction) is calculated. The answer is wrong.