What factors are resistance related to and what kinds of resistance are there

There are two main types of resistance in daily life.

1. It is friction. It has a relationship with the material, the roughness of the contact surface, and the pressure.

2. It is the resistance of the fluid, such as the resistance of air. It has to do with the shape and velocity of the object. The air resistance is directly proportional to the square of the velocity.

It is related to the roughness of the contact surface.

Frictional resistance, fluid resistance (object with air or water).

The force that prevents the movement of an object is called "resistance". A train running on a straight stretch of railroad is subjected to the traction of the locomotive and at the same time by the resistance of air and rails to it.

Introduction

Drag, also known as post-drag, air resistance, or fluid resistance, is the force produced by the relative motion of an object in a fluid that is opposite to the direction of motion. The direction of the drag force is opposite to the velocity of the flow field in which it is located. Generally, friction does not change with velocity, but drag does with velocity.

For an object moving in a fluid, the drag force is the sum of the components exerted by the surrounding fluid on the object, in the opposite direction of the direction of movement. The component of the applied force and the direction of movement perpendicular to it is generally regarded as lift. Therefore, the drag force and the direction of the object movement are just opposite, like when an airplane moves forward, a thrust is generated to overcome the effect of drag.

In space dynamics, atmospheric drag can be seen as the inefficiency of a spacecraft at launch, and its effect is that it requires additional energy at launch, but atmospheric drag helps the spacecraft slow down when returning to orbit, reducing the additional energy required to slow down, although the heat generated by atmospheric drag can even melt objects.

The driving resistance of a car can be divided into four types: rolling resistance, air resistance, slope resistance and acceleration resistance. Rolling resistance and air resistance are present in any condition in which the car is driven.

Slope resistance and acceleration resistance exist under certain driving conditions, such as when the car is driving at the same speed on a horizontal road, there is no slope resistance and acceleration resistance.

1 Rolling resistance.

Rolling resistance refers to the force that hinders the driving of the car caused by the deformation of the tires and road surface when the wheels of the car are rolling. When the wheel rolls, the contact area between the tire and the road surface, under the pressure of the heavy load, makes the parts of the tire circumference continue to be compressed and deformed, and then gradually recover the deformation. Due to the deformation, friction occurs between the rubber molecules of the tire, and the heat generated by the friction is constantly emitted to the atmosphere, so that the work done by the tire deformation cannot be fully recovered, which consumes the output power of the car and forms rolling resistance.

The deformation of the road surface will also form rolling resistance. When the car is driving on soft roads, such as dirt roads, desert roads, muddy roads, etc. The deformation of the road surface is obvious.

When a car passes, the soft road surface becomes permanently deformed, causing "ruts". The mechanical friction between the particles also consumes energy when the pavement is deformed, so the rolling resistance on a soft pavement is significantly greater than on a hard pavement.

Figure 2 2(a) and (b) show the general deformation of the tire and the road surface.

Figure 2-2 Formation of rolling resistance.

a) Deformation of the tire in the vertical direction (b) Deformation of the soft road surface.

In driving practice, it is important to know that when a car is driving at low speeds, the main part that constitutes the driving resistance is the rolling resistance.

Table 2-1 Rolling resistance coefficient (f) values of different pavement surfaces.

2 Air resistance.

When the car is driving, it will be relatively displaced with the surrounding air, so that the air in front of the car will be continuously squeezed out, forming a "pressure" of the oncoming air. The rear of the car cannot keep up with the driving speed of the car in time due to the speed of air flow, especially at high speed, a certain degree of vacuum will be formed in an instant, resulting in vortex and "suction". The air has a certain viscosity and friction with the moving car body to form resistance.

These pressures, suction forces, and friction forces are all the forces of air that hinder the movement of the car, which is called air resistance, see Figure 2 3(a), (b).

Figure 2-3 Air resistance of the car while driving.

a) Air pressure and friction (b) Air vortex.

The magnitude of air resistance is related to the windward area of the car, the driving speed, the degree of streamlining of the car's shape, wind force and wind direction.

The air resistance is proportional to the windward area; It is proportional to the square of the velocity. It can be seen that at high speeds, air resistance will become the main part of driving resistance.

Air resistance is directly proportional to the air resistance coefficient, so improving the shape design of the body and improving the streamlining degree of the body is of positive significance for reducing air resistance. The driver should be careful not to arbitrarily add parts that destroy the streamlined shape of the body. Cargo is loaded with as smooth transitions as possible, and the use of tarpaulin cover helps to reduce the coefficient of air resistance.

The main purpose is to train the muscles of the human body, and the traditional resistance training includes push-ups, dumbbells, barbells and other items. Resistance training is effective in enhancing physical fitness, developing muscles, and improving the body's metabolism, and it is also very beneficial. Modern people's life is becoming more and more sitting, and work and study require long hours of work in the neck and waist muscles.

If you do not train your neck and back muscles. Lack and deterioration of muscle strength can lead to muscle strain and changes in body shape. More and more people are suffering from cervical spine diseases and lumbar spine diseases.

Correct strength training can increase the strength of important parts, improve body shape, and increase flexibility.

1. Frictional resistance (between solids and solids) 2. Fluid resistance (between objects and air or water).

There are two main types of resistance in daily life.

1. It is friction.

The roughness of the contact surface with the material, land rent, and pressure has been weakened.

2. It is the resistance of the fluid, such as the resistance of air.

It has to do with the shape and velocity of the object. The air resistance is directly proportional to the square of the velocity.

Meaning of resistance:

1.A force that impedes the motion of an object. Such as: air resistance; Resistance of water.

2.Generally refers to the external force that hinders the development or progress of things.

Resistance [zǔ lì].

Citation: 2Ai Qing "Hymn to Light": "There are contradictions in unity, reversals in advance, resistance in movement, and betrayal in revolution." ”

Antonyms:

Unblocked [chàng tōng].

Interpretation: Passage or passage without hindrance.

Citations: 1Guo Moruo, Chapter 9, Chapter 4: "Since the launch of the offensive in mid-June, ......The Anqing (Anqing) and Hefei highways have been opened up, so that the march of the North Road is unimpeded. ”

2.Cao Jinghua "Flying Flower Collection: The Frontier Scenery is Infinitely Good": "Trains, cars, pedestrians, cars and horses are smooth at the same time. ”

synonyms:

obstruction [zǔ ài].

Interpretation: Blocking, so that it cannot pass or develop smoothly.

Citation: Mao Dun "Tan": "It's not that her father doesn't love her, but her father treats her mother poorly, and the situation hinders her bright and enthusiastic future." ”

Definition: Something that acts as a hindrance.

Citation: Mao Dun "The Story of the Big Nose": "At this moment, the head of the team seems to have hit an obstacle. ”

Question 1: In physics, what is resistance related to and how to find resistance In physics, what is resistance related to and how to find resistance.

The equilibrium means that the object is in a state of stationary or uniform linear motion when the force is applied, and the forces on the object are balanced with each other!

In junior high school, it is often found that the balance force is on the same straight line, that is, the two-force equilibrium condition Two forces acting on the same object, only if they are equal in magnitude and opposite directions, acting on the same straight line, the two forces balance each other!

Question 2: What factors are related to the magnitude of the resistance The resistance of an object moving in a fluid is proportional to the density of the fluid, the cross-sectional area (shape) of the object, and the square of the velocity of the motion.

Streamlined shapes can be used, such as objects such as jets or swordfish, which are streamlined to reduce drag and increase speed.

Question 3: Resistance-related factorsMotion is related to resistance, and what factors are resistance related to Resistance is a force named according to the effect of force, as long as the force that hinders the movement of an object is called resistance. Therefore, it is difficult to say what factors are related to the resistance.

But for the resistance of general motion, there are two types of forces: air resistance and frictional resistance. The magnitude of air resistance is related to the shape of the size of the windward side of the object and the velocity of the object relative to the air.

The frictional resistance is related to the pressure on the object and the properties of the contact surface (coefficient of friction).

Question 4: What are the factors related to the resistance of the fluid There are many things.